Method for decomposing polymer material, method for producing recycled resin, and method for recovering inorganic filler

ABSTRACT

The present invention is a method for decomposing a polymer material by chemically decomposing a polymer material containing a first monomer and a second monomer in a mixture of the polymer material with the first monomer or a derivative of the first monomer to produce a chemical raw material. A relationship between a proportion of number of molecules of the second monomer to number of molecules of the first monomer in a reaction system for decomposing the polymer material and the molecular weight of the chemical raw material produced in the reaction system is acquired in advance (S 101 ). Subsequently, an addition mount of the derivative of the first monomer to be added to the polymer material is determined based on the above relationship (S 102 ). The first monomer in the addition amount determined is then mixed with the polymer material (S 103 ).

TECHNICAL FIELD

The present invention relates to a method for decomposing a polymermaterial, a method for producing a recycled resin using a chemical rawmaterial produced by using the same, a recycled resin obtained by thesame, a recycled resin composition using the recycled resin, a methodfor recovering an inorganic filler, an inorganic filler obtained by thesame, and a polymer material containing the same.

BACKGROUND ART

Among plastics, a thermosetting resin exhibits excellent electricalinsulation, heat resistance and mechanical strength. Therefore, thethermosetting resin has been widely used as a material for electric andelectronic parts, automobile parts or the like.

When a thermosetting resin is once cured, it is not dissolved in asolvent either without being softened and melted due to heat.Accordingly, it has been technically difficult to regenerate a valuablechemical raw material from a cured product thereof. However, the need ofenvironmental preservation and building of a recycling based society hasbeen reviewed these days, and various researches on recycling ofthermosetting resins have been made.

In order to overcome these problems, Patent Document 1 discloses atechnology in which, while a phenol resin is dissolved in phenol that isa constituent monomer of the resin to decompose to a low molecularcompound such as phenol or the like, an organic filler is recovered.

Furthermore, Patent Document 2 discloses a technology in which alcoholin a supercritical state or subcritical state is brought into contactwith a phenol resin to decompose to and recover phenol. Patent Document2 further describes to the effect that a phenol resin may be producedthrough a reaction of the recovered phenol with formaldehyde.

However, according to the technologies of Patent Documents 1 and 2, theyield rate of the recycled thermosetting resin is not excellent.

In Patent Document 3, when the molecular weight distribution of anoligomer obtained by decomposing a thermosetting resin in asupercritical or subcritical state solvent becomes constant, recycle ofthe thermosetting resin has been carried out with the addition of amulti-functional compound. In this way, the quality of the recycledresin can be stabilized.

Furthermore, there has also been known a technology for improving thedecomposition efficiency of the aforementioned thermosetting resin. InPatent Document 4, there has been disclosed a technology for mixing athermosetting resin with a dispersing agent comprising a reactionsolvent and a phenol resin to obtain a slurry. Accordingly, there hasbeen disclosed that the stable high decomposition rate may be achievedby suppressing aggregation and sedimentation of a solid content in ahigh concentration slurry.

Furthermore, Patent Document 5 discloses that a phenol resin moldingmaterial having excellent mechanical strength is obtained with the useof a decomposed residue by adding a step of adjusting the decomposedresidue containing an inorganic filler of the aforementionedthermosetting resin to a specific range.

RELATED ART REFERENCES Patent Literatures

-   Patent Document 1: Japanese Unexamined Patent Application    Publication 2005-054138-   Patent Document 2: Japanese Unexamined Patent Application    Publication 2001-055468-   Patent Document 3: WO 2007/032047-   Patent Document 4: Japanese Unexamined Patent Application    Publication 2003-253041-   Patent Document 5: Japanese Unexamined Patent Application    Publication 2006-233141

DISCLOSURE OF THE INVENTION

However, in the technology of Patent Document 3, it has not been clearto how much extent the constituent monomer of the resin is present in areaction system to proceed with a target decomposition reaction of thethermosetting resin. Therefore, currently the constituent monomer hasbeen used in an excess amount. Accordingly, it is expected that thedecomposition reaction is carried out higher effectively by using theconstituent monomer in an appropriate amount.

Furthermore, according to the technology of Patent Document 4, since theresin component of the thermosetting resin or the organic filler issurely decomposed, it is expected that the inorganic filler may berecovered at a high purity. However, according to the knowledge of thepresent inventors, even though a molding material is produced by using arecovered product of the inorganic filler containing the resin componentundecomposed to some degree, a molding material having propertiescomparable to those of a virgin product may be obtained. Accordingly, ifthe residual ratio of the resin component is controlled, it is expectedthat the inorganic filler may be recovered according to the targetspecification. Further, if the decomposition rate is enhanced withoutusing a dispersing agent as disclosed in the technology of PatentDocument 4, the production process may be conducted more easily.

Also, in the technology of Patent Document 5, since there is a need of aprocess of adjusting the decomposed residue to a specific range,improvement of throughput has been in demand.

Furthermore, as described above, the decomposition reaction of acrosslinked polymer including a thermosetting resin has been used as ameans of recycling a polymer material. Therefore, a resin having astable quality may be highly effectively recycled by using a reagent inan appropriate amount, and it is expected that environmental load isreduced.

The present invention has been accomplished in view of the abovecircumstances, and a first object of the present invention is to enableto use monomers in an appropriate amount in a reaction system for thedecomposition reaction of a polymer material.

Furthermore, a second object of the present invention is to produce arecycled resin using monomers in an appropriate amount in a reactionsystem with respect to a chemical raw material obtained from thedecomposition reaction of a polymer material.

Furthermore, a third object of the present invention is to control thecontent of the resin component undecomposed in a method for recoveringan inorganic filler from the polymer material.

The present inventors have repeatedly been dedicated to study on thedecomposition reaction of a polymer material containing a resincomponent composed of a first monomer and a second monomer and as aresult, have found that a proportion of number of molecules of thesecond monomer to number of molecules of the first monomer in a reactionsystem and the molecular weight of the chemical raw material produced inthe decomposition reaction satisfy a specific relationship. Thus, thefirst invention has been completed.

Furthermore, the present inventors have repeatedly been dedicated tostudy on the method for producing a recycled resin from a decompositionproduct obtained by decomposing a polymer material containing a resincomponent composed of a first monomer and a second monomer and as aresult, have found that the proportion of number of molecules of thesecond monomer to number of molecules of the first monomer in a reactionsystem and the physical property of the recycled resin satisfy aspecific relationship. Thus, the second invention has been completed.

Also, the present inventors have repeatedly been dedicated to study onthe decomposition reaction of a polymer material containing a resincomponent composed of a first monomer and a second monomer and as aresult, have found that the proportion of number of molecules of thesecond monomer to number of molecules of the first monomer in a reactionsystem and the residual ratio of the resin component undecomposedcontained in the recovered inorganic filler satisfy a specificrelationship. Thus, the third invention has been completed.

That is, the first invention provides a method for decomposing a polymermaterial by chemically decomposing a resin component composed of a firstmonomer and a second monomer in a mixture of a polymer materialcontaining said resin component with said first monomer or a derivativeof said first monomer to produce a chemical raw material to be a rawmaterial for recycling said polymer material, comprising:

acquiring a relationship in advance between a proportion of number ofmolecules of said second monomer to number of molecules of said firstmonomer in a reaction system for decomposing said resin component and amolecular weight of said chemical raw material produced in said reactionsystem;

determining an addition amount of said first monomer or the derivativeof said first monomer to be added to said polymer material based on saidrelationship; and

mixing said first monomer or the derivative of said first monomer insaid addition amount determined with said polymer material.

Furthermore, the first invention provides a recycled resin compositionproduced by using the chemical raw material obtained by the above methodfor decomposing a polymer material.

The first invention also provides a method for producing a recycledresin in which the recycled resin is produced with the addition of amulti-functional compound to said chemical raw material obtained by theabove method for decomposing a polymer material.

The first invention also provides a recycled resin obtained by the abovemethod for producing a recycled resin.

The first invention also provides a recycled resin composition using therecycled resin obtained by the above method for producing a recycledresin.

According to the first invention, a relationship between the proportionof the number of molecules of the second monomer to the number ofmolecules of the first monomer in a reaction system and the molecularweight of the chemical raw material produced in the reaction system ispreviously acquired in advance, whereby the amount of the first monomerto be added to the polymer material is determined based on the acquiredrelationship, and then the first monomer in an appropriate amount ismixed with the polymer material in order to obtain a desired chemicalraw material. In this way, the polymer material may be decomposed byusing the first monomer of a requisite minimum amount. Accordingly,decomposition of the polymer material may be high effectively carriedout, and the environmental load can be reduced.

Furthermore, in the first invention, decomposition processing of thepolymer material may be carried out with the addition of the derivativeof the first monomer to the polymer material containing a resincomponent composed of a first monomer and a second monomer. The term“derivative of the first monomer” refers to those obtained by changing asubstituent other than an active group of the first monomer. However,when two or more active groups are present, those obtained bysubstituting an active group may be included. The term “active group ofthe first monomer” refers to a functional group to be a reactive pointreactive with the second monomer among functional groups of the firstmonomer.

Furthermore, according to the first invention, at determining theaddition amount of the first monomer, the above proportion correspondingto the molecular weight of the desired chemical raw material may beselected from the acquired relationship, and the addition amount of thefirst monomer may be determined so as to have the selected proportion ofthe number of molecules of the second monomer to the number of moleculesof the first monomer in a reaction system within the predeterminedrange.

The second invention provides a method for producing a recycled resin bychemically decomposing a resin component composed of a first monomer anda second monomer in a mixture of a polymer material containing saidresin component with said first monomer or a derivative of said firstmonomer, and mixing said resin component decomposed with said secondmonomer or the derivative of said second monomer to produce a recycledresin, comprising:

acquiring a relationship in advance between a proportion of number ofmolecules of said second monomer to number of molecules of said firstmonomer in a reaction system for producing said recycled resin from saidresin component decomposed and a physical property of said recycledresin;

determining an addition amount of said second monomer or the derivativeof said second monomer to be added to said resin component decomposedbased on said relationship; and

mixing said second monomer or the derivative of said second monomer insaid addition amount determined with said resin component decomposed.

According to the second invention, a relationship between the proportionof the number of molecules of the second monomer to the number ofmolecules of the first monomer in a reaction system and the physicalproperty of the recycled resin produced in the reaction system isacquired in advance, whereby the addition amount of the second monomerto be added to a decomposition product of the resin component composedof a first monomer and a second monomer is determined based on theacquired relationship, and then the second monomer in an appropriateamount is mixed with the decomposed resin component in order to obtain arecycled resin having physical property to be desired. In this way, therecycled resin may be produced by mixing the second monomer of arequisite minimum amount with the decomposed resin component.Accordingly, the yield rate of the recycled resin may be improved andthe environmental load may be reduced.

The second invention provides a method for producing a recycled resin bychemically decomposing a resin component composed of a first monomer anda second monomer in a mixture of a polymer material containing saidresin component with said first monomer or a derivative of said firstmonomer, and mixing said resin component decomposed with said secondmonomer or the derivative of said second monomer to produce a recycledresin, comprising:

adding said second monomer to a reaction system for producing saidrecycled resin from said resin component decomposed;

observing a physical property reflecting a molecular weight of saidrecycled resin produced in said reaction system;

determining an addition amount of said second monomer or the derivativeof said second monomer to be added to said resin component decomposedbased on a relationship between a proportion of number of molecules ofsaid second monomer to number of molecules of said first monomer in saidreaction system and said physical property; and

mixing said second monomer or the derivative of said second monomer insaid addition amount determined with said resin component decomposed.

The second invention also provides a recycled resin obtained by theabove method for producing a recycled resin.

The second invention also provides a recycled resin composition producedby using the above recycled resin.

According to the second invention, the physical property reflecting themolecular weight of the recycled resin produced in the reaction systemare observed with the addition of the second monomer to the reactionsystem for producing a recycled resin from the decomposed resincomponent, and the addition amount of the second monomer to be added tothe decomposed resin component is determined based on the relationshipbetween the proportion of the number of molecules of the second monomerto the number of molecules of the first monomer in the reaction systemand the physical properties. In this way, the recycled resin may beproduced by using the second monomer of a requisite minimum amount.Accordingly, the yield rate of the recycled resin may be improved andthe environmental load may be reduced.

Incidentally, in the second invention, the recycled resin may beproduced with the addition of the derivative of the second monomer tothe decomposed resin component. The term “derivative of the secondmonomer” refers to those obtained by changing a substituent other thanan active group of the second monomer. However, when two or more activegroups are present, those obtained by substituting an active group maybe included. The term “active group of the second monomer” refers to afunctional group to be a reactive point reactive with the first monomeramong functional groups of the second monomer.

In the second invention, at determining the addition amount of thesecond monomer to be added, the above proportion corresponding to thephysical property of the desired recycled resin may be selected from theacquired relationship, and the addition amount of the second monomer maybe determined so as to have the selected proportion of the number ofmolecules of the second monomer to the number of molecules of the firstmonomer in a reaction system within the predetermined range.

Meanwhile, the third invention provides a method for recovering aninorganic filler, comprising:

chemically decomposing a resin component composed of a first monomer anda second monomer in a mixture of a polymer material containing saidresin component and an inorganic filler with said first monomer or aderivative of said first monomer;

removing said resin component decomposed from a mixture of said polymermaterial with said first monomer or the derivative of said first monomerto calculate the residual ratio of said resin component undecomposed;

acquiring a relationship in advance between a proportion of number ofmolecules of said second monomer to number of molecules of said firstmonomer in a reaction system for decomposing said resin component andsaid residual ratio calculated;

determining an addition amount of said first monomer or the derivativeof said first monomer to be added to said polymer material based on saidrelationship;

mixing said first monomer or the derivative of said first monomer insaid addition amount determined with said polymer material; and

removing said resin component decomposed from the mixture of saidpolymer material with said first monomer or the derivative of said firstmonomer to recover said inorganic filler.

The third invention also provides an inorganic filler recovered by usingthe above method for recovering an inorganic filler.

The third invention further provides a polymer material containing theabove inorganic filler.

According to the third invention, a relationship between the proportionof the number of molecules of the second monomer to the number ofmolecules of the first monomer in a reaction system and the residualratio of the polymer material is acquired in advance, whereby theaddition amount of the first monomer to be added to the polymer materialis determined based on the acquired relationship, and the decompositionefficiency of the polymer material may be controlled. Accordingly, theinorganic filler containing the resin component undecomposed in adesired range to such a degree that can be recycled may be recovered andthe environmental load can be reduced.

Furthermore, according to the third invention, at determining theaddition amount of the first monomer, the above proportion correspondingto the desired residual ratio may be selected from the acquiredrelationship, and the addition amount of the first monomer may bedetermined so as to have the selected proportion of the number ofmolecules of the second monomer to the number of molecules of the firstmonomer in a reaction system within the predetermined range.

Incidentally, in the present invention, the term “polymer material”refers to a resin composition containing at least any one of athermoplastic resin and/or a thermosetting resin, and a product usingthe resin composition. The resin composition may be a composite materialcontaining a filler, an additive or the like.

The polymer material is not particularly limited, and examples thereofinclude molding materials or encapsulating materials containing athermosetting resin composition and an inorganic filler, laminate boardsproduced by impregnating the thermosetting resin composition in aninorganic base material or an organic base material, metal laminateboards obtained by adhering a metal foil, thermosetting resin productsand the like.

In the present invention, decomposition processing of the polymermaterial may be chemical decomposition processing of a polymer material,or may comprise chemical decomposition processing of a polymer material.Further, it may be solubilizing treatment of a polymer material, or maycomprise solubilizing treatment.

According to the present invention, using a reagent in an appropriateamount for decomposition processing of a polymer material, decompositionprocessing of a polymer material may be high effectively carried out andthe environmental load may be reduced.

According to the second invention, the second monomer in an appropriateamount is added to the chemical decomposition product of the resincomponent composed of a first monomer and a second monomer, whereby theyield rate is improved and the environmental load is reduced. Therefore,the recycled resin may be produced.

Furthermore, according to the third invention, the decompositionefficiency of the resin component contained in the polymer material maybe easily controlled, and the inorganic filler containing the resincomponent undecomposed in a desired range may be recovered.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages will be apparentfrom the following detailed description of the preferred embodiments inconjunction with the accompanying drawings.

FIG. 1 is a flow chart illustrating a decomposition method according toan embodiment.

FIG. 2 is a flow chart illustrating a method for producing a recycledresin according to an embodiment.

FIG. 3 is a schematic diagram illustrating a decomposition reactionaccording to an embodiment.

FIG. 4 is a view illustrating a relationship between the proportion ofthe number of molecules of the second monomer to the number of moleculesof the first monomer in a reaction system for decomposing a polymermaterial and the molecular weight of a chemical raw material produced inthe reaction system according to an embodiment.

FIG. 5 is a flow chart illustrating a method for recovering an inorganicfiller according to an embodiment.

FIG. 6 is a flow chart illustrating a process of obtaining a chemicalraw material and an inorganic filler from a polymer material.

FIG. 7 is a flow chart illustrating a method for producing a recycledresin according to an embodiment.

FIG. 8 is a flow chart illustrating a modified example of a method forproducing a recycled resin according to an embodiment.

FIG. 9 is a view illustrating the results of Example 1.

FIG. 10 is a view illustrating the results of Example 1.

FIG. 11 is a view illustrating the results of Example 2.

FIG. 12 is a view illustrating the results of Example 3.

FIG. 13 is a view illustrating the results of Example 3.

FIG. 14 is a view illustrating the results of Example 4.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention will be describedreferring to the drawings. Incidentally, in all drawings, the samecomponents are assigned the same reference numerals and appropriateexplanations thereof will be omitted.

First Embodiment

This embodiment relates to a method for decomposing a polymer materialby chemically decomposing a resin component in a mixture of the polymermaterial containing the first monomer and the second monomer with thefirst monomer or a derivative of the first monomer to produce a chemicalraw material to be a raw material for recycling the polymer material. Inthe present invention, the term “chemical raw material” refers to adecomposition product of a resin component comprising monomers,oligomers or a mixture thereof.

FIG. 1 is a flow chart illustrating a method for decomposing a polymermaterial of the embodiment. As shown in FIG. 1, first, a relationshipbetween a proportion of number of molecules (amount of substance) of thesecond monomer to number of molecules (amount of substance) of the firstmonomer in a reaction system for decomposing the resin component and amolecular weight of the chemical raw material produced in the reactionsystem is acquired in advance (S101). Subsequently, an addition amountof the first monomer to be added to the polymer material is determinedbased on the above relationship (S102). The first monomer in theaddition amount determined is then mixed with the polymer material(S103). Thereafter, the first monomer is made into a supercritical stateor subcritical state (S104). Accordingly, decomposition processing ofthe polymer material proceeds to obtain a chemical raw material (S105).

Hereinafter, the method for decomposing a polymer material of theembodiment will be described in detail.

FIG. 3 illustrates a schematic diagram of the reaction system fordecomposing a polymer material. The resin component contained in thepolymer material is composed of the first monomer (molecular weight: α)and the second monomer (molecular weight: β) bonded by a chemical bond.When the first monomer or its derivative is added to this polymermaterial, the first monomer is reacted with the resin component. Forexample, as shown in FIG. 3( a), when 1 molecule of the first monomer isadded to 1 molecule of the resin component having a molecular weight(4α+5β), the first monomer is added to the resin component so that 1molecule of a chemical raw material having a molecular weight (5α+5β) isproduced. In addition, as shown in FIG. 3( b), when 2 molecules of thefirst monomer are added to 1 molecule of the above resin component, theresin component is decomposed so that 2 molecules of a chemical rawmaterial having a number average molecular weight {(6α+5β)/2} areproduced. Furthermore, as shown in FIG. 3( c), when 4 molecules of thefirst monomer are added to 1 molecule of the above resin component, theresin component is decomposed so that 3 molecules of a chemical rawmaterial having a number average molecular weight {(8α+5β)/3} areproduced.

Then, in S101, the proportion of the number of molecules of the secondmonomer to the number of molecules of the first monomer in the reactionsystem is plotted on the transverse axis while the number averagemolecular weight (Mn) of the chemical raw material produced is plottedon the vertical axis. In this way, a graph as shown in FIG. 4 isacquired. When the proportion of the number of molecules of the secondmonomer to the number of molecules of the first monomer is not less than1.0, an addition reaction for adding the first monomer to the polymermaterial proceeds, so that the molecular weight of the chemical rawmaterial produced may not be controlled. However, when the proportion ofthe number of molecules of the second monomer to the number of moleculesof the first monomer becomes less than 1.0, the decomposition reactionof the polymer material proceeds. At this time, when the proportion ofthe number of molecules of the second monomer to the number of moleculesof the first monomer is in a specified range, this proportion and themolecular weight of the chemical raw material produced are approximatelyproportional to each other. When the proportion of the number ofmolecules of the second monomer to the number of molecules of the firstmonomer reaches a predetermined value, the number average molecularweight of the chemical raw material produced becomes constant as well.

Incidentally, the weight average molecular weight (Mw) may be plotted onthe vertical axis in place of the number average molecular weight (Mn)of the chemical raw material produced.

Subsequently, in S102, the amount of the first monomer to be added isdetermined based on the graph illustrated in FIG. 4. Specifically, amechanism of the decomposition reaction is predicted from the proportionof the number of molecules of the second monomer to the number ofmolecules of the first monomer of the polymer material, and the range ofthe target molecular weight is determined in advance. The range of theproportion of the number of molecules of the second monomer to thenumber of molecules of the first monomer is determined, and according tothe determined range, the addition amount of the first monomer added isdetermined.

Incidentally, in S101, the molecular weight of the chemical raw materialcorresponding to arbitrary two points may be examined in the ranges inwhich the proportion of the number of molecules of the second monomer tothe number of molecules of the first monomer in the reaction system isin the range of less than 1.0. At this time, in S102, the additionamount of the first monomer is determined from the above proportion andthe molecular weight of the chemical raw material supplementing theobtained two points.

The first monomer in the amount determined in S102 is added and mixed tothe polymer material (S103). Thereafter, the first monomer is made intoa supercritical state or subcritical state (S104). At this time, areaction solvent may be added together with the first monomer.

Here, in the present invention, the term “supercritical state” refers toa state in which both temperature and pressure are higher than thecritical point (critical temperature, critical pressure) of the firstmonomer or the reaction solvent. In the supercritical state, the firstmonomer dissolves a substance easily, thus exhibiting great diffusionrate, and has both properties of a liquid and a gas. The term“subcritical state” refers to a region in the vicinity of the criticalpoint in which both temperature and pressure are a little lower than thecritical point or a region in the vicinity of the critical point inwhich any one of temperature or pressure is a little lower than thecritical point.

Next, the range of the temperature and pressure in the supercriticalstate or the subcritical state of the first monomer or the reactionsolvent in the present invention will be described. The criticaltemperature of the first monomer is taken as Tc [K], while the criticalpressure thereof is taken as Pc [MPa]. The reduction temperatureobtained by dividing a temperature of T [K] by the critical temperatureis taken as Tr (=T/Tc), while the reduction pressure obtained bydividing a pressure of P [MPa] by the critical temperature is taken asPr (=P/Pc).

In the present invention, the term “supercritical state or subcriticalstate” specifically refers to a state of the temperature (T) andpressure (P) in which the mixture of the polymer material with the firstmonomer is in the range of 0.7≦Tr≦1.3 and 0.3≦Pr≦6.0, and preferably inthe range of 0.8≦Tr≦1.2 and 0.4≦Pr≦4.0. In the present invention, in theabove range of the temperature (T) and pressure (P), 1.0≦Tr and 1.0≦Prare defined as the supercritical state, and the other range is definedas the subcritical state.

Hereinafter, the range of the specific temperature and pressure will beexemplified. When the first monomer is phenol, the critical temperatureof phenol is 694 K (421° C.) and the critical pressure is 6.1 MPa. So,the term “supercritical state or subcritical state” refers to a state inwhich the temperature is in the range of 486 K (213° C.) or more and 902K (629° C.) or less, and the pressure is in the range of 1.8 MPa or moreand 36.6 MPa or less. Preferably, the temperature is in the range of 555K (282° C.) or more and 833 K (560° C.) or less, and the pressure is inthe range of 2.4 MPa or more and 24.4 MPa or less.

When methanol is used as a reaction solvent, the critical temperature ofmethanol is 513 K (240° C.) and the critical pressure is 8.1 MPa. So,the term “supercritical state or subcritical state” refers to a state inwhich the temperature is in the range of 359 K (86° C.) or more and 667K (394° C.) or less, and the pressure is in the range of 2.4 MPa or moreand 48.6 MPa or less. Preferably, the temperature is in the range of 410K (137° C.) or more and 616 K (343° C.) or less, and the pressure is inthe range of 3.2 MPa or more and 32.4 MPa or less.

When water is used as a reaction solvent, the critical temperature ofwater is 648 K (374° C.) and the critical pressure is 22.1 MPa. So, theterm “supercritical state or subcritical state” refers to a state inwhich the temperature is in the range of 453 K (180° C.) or more and 841K (568° C.) or less, and the pressure is in the range of 6.6 MPa or moreand 132.6 MPa or less. Preferably, the temperature is in the range of518 K (245° C.) or more and 776 K (503° C.) or less, and the pressure isin the range of 8.8 MPa or more and 88.4 MPa or less.

As described above, the first monomer or the reaction solvent and amixture thereof are made into a supercritical state or subcriticalstate, whereby decomposition processing of the polymer material proceedsand a predetermined post treatment is carried out to recover a productcontaining the chemical raw material.

The polymer material may be recycled from the chemical raw materialcontained in the thus-obtained recovered product.

According to the embodiment, the derivative of the first monomer inplace of the first monomer may be added to the polymer material toobtain a chemical raw material. A resin different from the polymermaterial decomposed by using the thus-obtained chemical raw material maybe produced.

The polymer compound produced from the chemical raw material obtained inthe embodiment is hereinafter referred to as a recycled resin.

FIG. 2 illustrates a flow chart explaining a method for producing arecycled resin using the decomposition processing of the embodiment.

First, in S201, decomposition processing of the polymer material in theembodiment as shown in FIG. 1 is carried out to obtain a chemical rawmaterial. Then, in S202, a recycled resin is produced from the chemicalraw material obtained in S201.

Specifically, in S202, a multi-functional compound is added to thechemical raw material produced in S201. As the multi-functionalcompound, there may be used a second monomer or a derivative of thesecond monomer.

Hereinafter, the decomposition reaction of the polymer material to becarried out in the embodiment will be described in more detail.

For the decomposition reaction of the polymer material to be carried outin the embodiment, the chemical raw material is obtained by conductingdecomposition and/or solubilization of the polymer material in asupercritical state or subcritical solvent having a first monomer as anessential component in a heating and pressurizing vessel.

(a) Polymer Material

In the embodiment, the polymer material to be decomposed is composed ofa first monomer and a second monomer. Specifically, a straight chainpolymer and/or a crosslinked polymer are used for the polymer material.The straight chain polymer is selected from a thermoplastic resin suchas polyethylene terephthalate, polybutylene terephthalate, polyphenylenesulfide, nylon 66 and the like, while the crosslinked polymer isselected from the group consisting of a thermosetting resin, aphotocurable resin and a radical-curable resin.

The thermosetting resin to be applied to the embodiment is notparticularly limited. A phenol resin, an epoxy resin, a melamine resinand a urea resin may be particularly effectively applied. Furthermore,more preferably used are those containing a phenol resin.

Examples of such a phenol resin include novolac type phenol resins suchas a phenol novolac resin, a cresol novolac resin, a bisphenol A novolacresin and the like; and resol type phenol resins such as an unmodifiedresol phenol resin, and an oil-modified resol phenol resin modified bypaulownia oil, linseed oil, walnut oil or the like.

(b) First Monomer

Examples of the first monomer used in the embodiment include a phenolcompound, urea, a melamine compound, and derivatives of the monomers.

As such a first monomer, for example, a phenol compound in which atleast one of hydrogen atoms bonded to a carbon atom of an aromatic ringis substituted by a hydroxyl group may be selected. This phenol compoundfunctions as a solvent as a single solvent or a mixture with othersolvent in supercritical or subcritical state and is capable ofdecomposing and/or solubilizing the polymer material. Examples of thephenol compound include phenol; cresols such as o-cresol, m-cresol,p-cresol and the like; xylenols such as 2,3-xylenol, 2,4-xylenol,2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol and the like;trimethylphenols such as 2,3,5-trimethylphenol and the like;ethylphenols such as o-ethylphenol, m-ethylphenol, p-ethylphenol and thelike; alkylphenols such as isopropylphenol, butylphenol, t-butylphenoland the like; o-phenylphenol; m-phenylphenol; p-phenylphenol; catechol;naphthalenediols such as 1,5-dihydroxynaphthalene,1,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene and the like;polyhydric phenols such as resorcin, catechol, hydroquinone, pyrogallol,phloroglucin and the like; and alkyl polyhydric phenols such asalkylresorcin, alkylcatechol, alkylhydroquinone and the like. Amongthese, preferably used are phenols from the viewpoints of the cost andan effect imparting to the decomposition reaction.

Alternatively, as the first monomer, melamine compounds may be selected.As the melamine compound, melamine or a compound such as acetoguanamineand benzoguanamine in which an amino group of melamine is substituted byother functional group is suitably used.

As the first monomer, one kind or a combination of two or more kindsthereof may be used.

(c) Second Monomer

As the second monomer constituting the polymer material used in theembodiment, a multi-functional compound is used. Examples of themulti-functional compound include aldehyde compounds, of which aformaldehyde compound is suitably used. Examples of the formaldehydecompound include formaldehyde, paraformaldehyde, trioxane, acetaldehyde,propionaldehyde, polyoxymethylene, chloral, hexamethylenetetramine,fulfral, glyoxal, n-butylaldehyde, caproaldehyde, allylaldehyde,benzaldehyde, crotonaldehyde, acrolein, tetraoxymethylene,phenylacetaldehyde, o-tolualdehyde, salicylaldehyde,dihydroxybenzaldehyde, trihydroxybenzaldehyde,4-hydroxy-3-methoxyaldehyde paraformaldehyde and the like.

As the second monomer, one kind or a combination of two or more kindsthereof may be used.

(d) Processing Conditions

The decomposition processing conditions of the polymer material may wellrender a solvent having a first monomer as an essential component in asupercritical state or subcritical state, and this may be achieved bycontrolling mainly a temperature and pressure. Besides, a decompositionprocessing apparatus may be any type capable of conducting theseprocessing conditions, and may be any of batch type, semi-batch type orcontinuous type.

The polymer material may contain a cured resin, an uncured or half-curedresin, a varnish containing these resins or the like.

The polymer material is not particularly limited, and examples thereofinclude encapsulating materials comprising a thermosetting resincomposition containing an epoxy resin, a phenol resin, a polyimideresin, a benzocyclobutene resin or the like, and an inorganic fillersuch as silica or the like. Furthermore, laminate boards produced byimpregnating in an inorganic base material such as a glass nonwovenfabric or an organic base material such as paper and cloth, metal-cladlaminate boards obtained by adhering a metal foil such as a copper foilor the like, and thermosetting resin products such as printed circuitboards obtained by processing the copper-clad laminate boards may beused as the polymer material.

Furthermore, other examples of the polymer material include moldingmaterials using a thermosetting resin composition, and thermosettingresin products such as a foam material, a friction material, a castmetal, an adhesive, a refractory material, whetstone or the like. Theterm “thermosetting resin composition” refers to, for example, thoseobtained by combining an inorganic filler such as silica, calciumcarbonate, aluminum hydroxide, glass fiber or the like, an organicfiller such as wood powder or the like, a rubber ingredient, or otheradditive with a thermosetting resin such as a novolac type phenol resin,a resol type phenol resin, an alkyl-modified phenol resin, aphenoxy-modified phenol resin, a phenol resin modified by oil such ascashew or the like, a melamine resin, a urea resin or the like.

When the polymer material to be provided for the processing is a solidform, the shape and size thereof are not particularly restricted. Thesolid polymer material may be pulverized to an appropriate sizeconsidering necessary cost for pulverization and the decomposition rate.Usually, a particle diameter is not more than 1,000 μm, preferably notmore than 500 μm, and further preferably not more than 250 μm. Withinthe range of the aforementioned particle diameter, a decompositionprocessing step may be conducted in a short time and is effective. Onthe other hand, when the particle diameter is less than theaforementioned lower limit, in the pulverization step before thedecomposition processing step, an enormous increase of cost involved inpulverization is resulted in some cases. Even for pulverization to lessthan the above lower limit, in the subsequent decomposition processingstep, the decomposition efficiency does not become excellent. When it isgreater than the aforementioned upper limit, the decompositionefficiency in relation to the specific surface area is worsened, anddepending on the circumstances, the polymer material may not beprecipitated and decomposed in some cases. Accordingly, in theaforementioned range of the particle diameter, a particle diameter forbalancing both of the decomposition processing step and pulverizationstep may be selected.

The first monomer may contain one obtained when the polymer material ofthe embodiment is subjected to decomposition, followed by separating andpurifying.

Meanwhile, the first monomer may be used in combination with othersolvent. As other solvent, all that are used as a solvent in an ordinarychemical reaction such as water, alcohols such as methanol and ethanol,glycols such as ethylene glycol and propylene glycol, ketones, ethers,esters, organic acids and acid anhydrides may be used. Furthermore, aplurality of solvents may be used. Among the solvents, from theviewpoints of an effect imparting to the decomposition reaction and easyavailability, water is preferred. Furthermore, the mixing ratio of theother solvent to the constituent monomers is preferably from 1 to 500parts by weight and more preferably from 5 to 50 parts by weight, basedon 100 parts by weight of the first monomer.

As the temperature, the reduction temperature (Tr) is usually preferablyin the range of 0.7≦Tr≦1.3, and more preferably in the range of0.8≦Tr≦1.2. When the temperature is too low, the decomposition rate ofthe polymer material may be lowered and processing in a short time maybe difficult in some cases. When the temperature is, on the contrary,too high, side reactions such as a pyrolysis reaction and a dehydrationreaction may be accompanied to vary a chemical structure of the chemicalraw material, so that the reuse of the chemical raw material may bedifficult in some cases. That is, when the temperature is set in theabove range, the method is excellent in a balance between maintenance ofthe high decomposition rate and suppression of the side reaction.

Furthermore, as the pressure, the reduction pressure (Pr) is usuallypreferably in the range of 0.3≦Pr≦6.0, and more preferably in the rangeof 0.4≦Pr≦4.0. When the pressure is too low, the first monomer does notbecome a supercritical state or subcritical state but becomes a vapor orgas state, so that the decomposition rate may be lowered in some cases.On the other hand, when the pressure is too high, a unit operable undermore severe conditions may be necessary, energy necessary formaintaining high pressure may be increased, the decomposition rate maybe hardly improved, and an outstanding effect may not be obtained insome cases. When the pressure is set in the above range, the method isexcellent in a balance between maintenance of the high decompositionrate and suppression of the energy consumption.

Furthermore, decomposition processing may be continued until themolecular weight distribution (Mw/Mn) of the chemical raw materialreaches a specified value. The reaction time is from about 1 to 60minutes, and preferably from about 3 to 30 minutes.

The method of the embodiment is preferable as a method for decomposing apolymer material to a chemical raw material having a molecular weight(Mw) of 2.0×10² or more and 2.5×10³ or less. This molecular weight, incase of the phenol resin, corresponds to 2 to 25 nuclei. Morepreferably, the molecular weight may be in the range of 2.0×10² or moreand 1.5×10³ or less, and this molecular weight, in case of the phenolresin, corresponds to 2 to 15 nuclei. The term “molecular weight of thechemical raw material” mentioned herein means that the resin componentcontained in the chemical raw material has a molecular weight shownherein and is contained in an amount of not less than 50% by weight. Themolecular weight distribution (Mw/Mn) of the chemical raw material uponcompletion of the processing is preferably in the range of 1.0 or moreand 3.0 or less, and more preferably in the range of 1.0 or more and 2.0or less. In the embodiment, since the chemical raw material having aspecified molecular weight distribution is obtained, the quality of therecycled resin obtained in the next step becomes stable.

Incidentally, the molecular weight distribution (Mw/Mn) of the chemicalraw material upon completion of the decomposition processing is suitablymeasured by the use of gel permeation chromatography (GPC). As specificexamples of measurement units and conditions at that time, two of TSKgelGMHL and two of TSKgel G2000HL manufactured by Tosoh are used as aseparation column, tetrahydrofuran is used as an eluent, a calibrationcurve is obtained in terms of polystyrene, a differential refractiveindex meter is used as a detector, a flow rate is set to 1 cm³/min, anda temperature is set to 40° C.

The decomposition processing of the embodiment, from the viewpoint ofimproving the processing rate, is preferably carried out in the presenceof a base catalyst. The base catalyst at that time is not particularlyrestricted, and examples thereof include a Broensted base, a Lewis base,or natural inorganic and organic compounds, and compounds showing anequivalent effect upon hydration with a metal oxide. One kind or acombination of two or more kinds thereof may be used.

Concrete examples of the base catalyst include inorganic compounds suchas beryllium hydroxide, sodium hydroxide, magnesium hydroxide, potassiumhydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, anoxide showing an equivalent effect upon hydration and the like; andorganic compounds including amines such as pyridine and triethylamine,amidines such as acetamidine and benzylamidine, ammonium salts such asdiazobicycloundecane, phosphonium salts such as tetrabutylphosphoniumhydroxide, and the like.

The chemical raw material obtained by the decomposition method of theembodiment as described above is reacted with a multi-functionalcompound, whereby the recycled resin may be produced. At this time, asthe chemical raw material, the recovered product after completion of thedecomposition processing step (S201) may be used as it is. As themulti-functional compound, a second monomer or a derivative of thesecond monomer may be used.

The recycled resin may be obtained, for example, in a known methodillustrated in Patent Document 3. As for a typical example of a chemicalstructure of the recycled resin, when a phenol resin is used as apolymer material, there is exemplified a novolac type phenol resin wherenuclei of a phenol skeleton form a methylene bond. When the polymermaterial is a melamine resin, there is exemplified a melamine resinwhere nuclei of a melamine skeleton form a methylene bond. When thepolymer material is a urea resin, there is exemplified a urea resinwhere nuclei of a urea skeleton form a methylene bond. When the polymermaterial is an epoxy resin, there is exemplified a compound having astructure where nuclei of a main skeleton of the epoxy resin form amethylene bond such as bisphenol A, bisphenol F, a phenol novolac resin,a cresol novolac resin or the like. Incidentally, when epichlorhydrineis further added to and reacted with the recycled resin obtained fromthe aforementioned epoxy resin, there is exemplified a compound having astructure where the recycled resin is epoxidized. Furthermore, when thethermosetting resin that is a raw material contains a phenol resin, amelamine resin, a urea resin or an epoxy resin, there are exemplifiedstructures where the respective resins and respective nuclei of thephenol skeletons, melamine skeletons, urea skeletons or main skeletonsof the epoxy resin are copolymerized through a methylene bond. However,the chemical structures are only one example and the obtained recycledresin usually has a polymer component having a molecular weight in therange of 2.0×10² to 1.0×10⁵ as a main portion, and a molecular weightdistribution (Mw/Mn) preferably in the range of 2.0 or more and 15 orless, and more preferably in the range of 3.0 or more and 10 or less.Herein, the term “molecular weight of the recycled resin component”refers to a weight average molecular weight (Mw).

The molecular weight in the range of 2.0×10² to 1.0×10⁵ is substantiallythe same as that of a prepolymer used for the production of a polymermaterial, so that it may be reused as a prepolymer by carrying outpurification as needed. Here, the term “polymer component having amolecular weight in the range of 2.0×10² to 1.0×10⁵ as a main portion”means that a polymer component having a molecular weight shown herein iscontained not less than 50% by weight. However, other than the polymercomponent having a molecular weight of the main portion, a polymercomponent having a molecular weight exceeding 1.0×10⁵ may be containedas well. The polymer component having a molecular weight in the range of2.0×10² to 1.0×10⁵, in the case of the usual polymer material,corresponds to about 2.0 to 1.0×10³ nuclei of raw material monomers.Furthermore, a compound that mainly has a polymer component having amolecular weight in the range of 2.0×10² to 1×10⁵ contains not only acomponent obtained from a polymer material but also a component obtainedfrom an organic filler or a base material contained in the polymermaterial in some cases.

Herein, the obtained recycled resin, after a solvent, a residue and thelike are separated, may be reused as a raw material of the recycledresin composition. The method of separation is not particularly limited,and is used in a usual solid-liquid separation. Processes such ascyclone, filtration, gravitational sedimentation and the like are cited.Furthermore, the recycled resin mainly made of a polymer componenthaving a molecular weight in the range of 2.0×10² to 1.0×10⁵, and amixture containing a processed and recovered product of the polymermaterial may be diluted in an organic solvent, and then a solid-liquidseparation operation such as such as cyclone, filtration, gravitationalsedimentation or the like may be conducted.

Furthermore, in the embodiment, unreacted first monomers are separated,and this is newly reused in the decomposition processing of the polymermaterial. Furthermore, the recycled resin mainly made of a polymercomponent having a molecular weight in the range of 2.0×10² to 1.0×10⁵is distilled or extracted to separate and recover first monomers whichmay be reused. Herein, a method of separating unreacted first monomersis not particularly limited, and anyone of methods such as flashdistillation, reduced-pressure distillation, solvent extraction and thelike may be employed. Furthermore, according to the construction of theembodiment, first monomers of a requisite minimum amount may beintroduced into the reaction system, so that the above reuse operationbecomes simpler than in the past.

Furthermore, in the obtained recycled resin, the unreacted reactionreagent such as the first monomer, the second monomer, water or the likemay be contained in a small amount, in addition to the above polymercomponent having a molecular weight in the range of 2.0×10² to 1.0×10⁵.

Next, an operational effect of the embodiment will be described.According to the method in the embodiment, a relationship between theproportion of the number of molecules of the second monomer to thenumber of molecules of the first monomer in a reaction system and themolecular weight of the chemical raw material produced in the reactionsystem is acquired in advance, whereby the addition amount of the firstmonomer or the derivative of the first monomer to be added to thepolymer material is determined based on the acquired relationship, andthen the first monomer in an appropriate amount is mixed with thepolymer material in order to obtain a desired chemical raw material. Inthis way, in the mixture of the first monomer of a requisite minimumamount the polymer material may be decomposed. Accordingly,decomposition processing of the polymer material may be highlyeffectively carried out and the environmental load can be reduced.

Furthermore, the polymer material may be recycled by using the chemicalraw material obtained by the decomposition processing method of theembodiment. Furthermore, the derivative of the first monomer in S102 isadded, or the derivative of the second monomer in S202 is used, wherebyan arbitrary recycled resin may be produced. Accordingly, the recycledresin may be obtained without using a reagent in an excess amount, andit may be possible to provide a recycling means with much reduced loadto the environment.

Second Embodiment

FIG. 5 is a flow chart illustrating a method for recovering an inorganicfiller of the embodiment. The method for recovering an inorganic fillercomprises chemically decomposing a resin component composed of a firstmonomer and a second monomer in a mixture of a polymer materialcontaining the resin component and an inorganic filler with the firstmonomer or a derivative of the first monomer (S301);

removing the resin component decomposed from the mixture of the polymermaterial with the first monomer or the derivative of the first monomerto calculate a residual ratio of the resin component undecomposed(S302);

acquiring a relationship in advance between a proportion of number ofmolecules of the second monomer to number of molecules of the firstmonomer in a reaction system for decomposing the resin component and theresidual ratio calculated (S303);

determining an addition amount of the first monomer to be added to thepolymer material based on the above-stated relationship (S304);

mixing the first monomer in the addition amount determined with thepolymer material (S305); and

removing the resin component decomposed from the mixture of the polymermaterial with the first monomer to recover an inorganic filler (S306).

Hereinafter, the embodiment will be illustrated in detail using FIGS. 5and 6. FIG. 6 is a flow chart illustrating a process of obtaining achemical raw material and an inorganic filler from a polymer material.

[S301: Decomposition Processing of the Polymer Material]

First, a polymer material comprising a resin component composed of afirst monomer and a second monomer and an inorganic filler is prepared.As the polymer material, those exemplified in the first embodiment maybe used. Furthermore, as the first monomer and the second monomer, thoseexplained in the first embodiment may be used.

In the embodiment, examples of the inorganic filler include oxidesilicon such as silica, glass fiber, carbon fiber, calcium carbonate,glass beads, aluminum hydroxide, clay, calcined clay, talc, diatomaceousearth, alumina, magnesium oxide and magnesium hydroxide.

Subsequently, the resin component is chemically decomposed with theaddition of the first monomer to the polymer material. At this time, thefirst monomer may be used in combination with other solvent. As othersolvent, those exemplified in the first embodiment may be used.

Herein, the mixture of the first monomer in a mixture of the firstmonomer and the polymer material with other solvent is made into asupercritical state or subcritical state. In this way, the resincomponent may be decomposed in a short reaction time without addition ofan acid catalyst or a base catalyst. However, for the purpose of thedecomposition at a much lower reaction temperature in a much shorterreaction time, an acid catalyst or a base catalyst may be used. Thetemperature and pressure at this time may be the same as those in S104explained in the first embodiment.

[S302: Evaluation of the Residual Ratio of the Resin ComponentUndecomposed]

After completion of the decomposition reaction, an arbitrary solvent isadded to the decomposition product. The solvent used herein may beselected from those which dissolve the decomposed resin component and donot dissolve the resin component undecomposed and inorganic filler.Then, the product is filtered with a filter and the filtrate is asoluble content. Further, the residue remained in the filter afterfiltration is an insoluble content. A pore diameter of the filter may begood as long as the resin component undecomposed and inorganic fillerremain, and it is preferably from 0.1 to 10 μm. Then, the insolublecontent is subjected to an incineration treatment and weighed. Theresidual ratio may be determined according to Formula 1.Residual ratio[%] of unreacted resin component contained in inorganicfiller recovered product (1)=[{weight (g) of inorganic filler recoveredproduct (1)−weight (g) of residue after incineration (2)}/weight (g) ofinorganic filler recovered product (1)]×100  Formula 1

[S303: Acquisition of Data on a Relationship Between the Molar Ratio ofthe Second Monomer to the First Monomer in a Reaction System and theResidual Ratio of the Resin Component Undecomposed]

In S303, the proportion of the number of molecules of the secondmonomers to the number of molecules of the first monomer in a reactionsystem is plotted on the transverse axis, and as a result of evaluationof S302, the obtained residual ratio is plotted on the vertical axis. Asexplained in the first embodiment, when the proportion of the number ofmolecules of the second monomer to the number of molecules of the firstmonomer becomes less than 1.0, the decomposition reaction of the polymermaterial proceeds. At this time, when the proportion of the number ofmolecules of the second monomer to the number of molecules of the firstmonomer is in the predetermined range, this proportion and the molecularweight of the chemical raw material produced are approximatelyproportional to each other. When the proportion of the number ofmolecules of the second monomer to the number of molecules of the firstmonomer reaches a certain predetermined value, the number averagemolecular weight and the weight average molecular weight of the chemicalraw material produced become constant as well. The decomposition rate isdefined as the proportion of the resin component contained in thepolymer material decomposed to the chemical raw material. Therefore,according to this principle, when the proportion of the number ofmolecules of the second monomer to the number of molecules of the firstmonomer is in the predetermined range, this proportion and thedecomposition rate of the resin component are approximately proportionalto each other. When the proportion reaches a certain predeterminedvalue, the decomposition rate reaches 100%. Furthermore, the residualratio is theoretically defined as the content of the resin componentundecomposed contained in the decomposition product. So, the proportionof the number of molecules of the second monomer to the number ofmolecules of the first monomer and the residual ratio are approximatelyproportional to each other. When the proportion reaches a certainpredetermined value, the residual ratio reaches 0%.

[S304: Determination of the Addition Amount of the First Monomer to beAdded to the Polymer Material]

Next, the addition amount of the first monomer or the derivative of thefirst monomer to be added to the polymer material is determined based onthe proportional relationship obtained in S303. Specifically, the rangeof the residual ratio in the target polymer material is determined inadvance from the proportion of the number of molecules of the secondmonomer to the number of molecules of the first monomer. The range ofthe proportion of the number of molecules of second monomer to thenumber of molecules of the first monomer is determined, and according tothe determined range, the addition amount of the second monomer to beadded is determined. At this time, it is preferable to select theproportion to make the residual ratio of the resin component to not morethan 10%, and it is more preferable to select the proportion to make theresidual ratio to not more than 5%. In this way, a high quality polymermaterial can be produced by using the recovered inorganic filler.Besides, the residual ratio corresponding to arbitrary two points may beexamined. At this time, the addition amount of the first monomer to beadded is determined from the above proportion and the residual ratiosupplementing the obtained two points. Then, the number of molecules ofthe first monomer and the number of molecules of the second monomerconstituting the resin component contained in the decomposed polymermaterial are calculated, and the addition amount of the first monomer tobe added is selected so as to be the selected proportion of the secondmonomer to the first monomer in the reaction system. In this way, theinorganic filler containing the resin component in an arbitrary range tosuch a degree that can be reused may be recovered.

[S305: Mixing of the First Monomer with the Polymer Material]

Subsequently, the first monomer in the addition amount determined inS304 is added to and mixed with the polymer material, and then the firstmonomer is made into a supercritical state or subcritical state in thesame manner as in S301 to carry out decomposition processing of thepolymer material. At this time also, as in S301, the first monomer maybe mixed as other solvent. Furthermore, the derivative of the firstmonomer in place of the first monomer may be added to the polymermaterial.

[S306: Recovery of the Inorganic Filler]

Then, the product after the decomposition processing is dissolved in anddiluted with an arbitrary solvent, and then filtered with a filter. Thepore diameter of a filter may be the same as that used in S302. Theinsoluble content remained in the filter is dried to recover theinorganic filler.

The recovered inorganic filler may be reused as a filler of the polymermaterial such as plastic or the like. As the method of reuse, forexample, when it is reused as a raw material of a thermosetting resinmolding material, the inorganic filler recovered product may be mixedwith other raw material and reused by a known production method. At thistime, the recovered inorganic filler alone may be used as a raw materialwithout using a novel inorganic filler, or other chemical raw materialand/or filler may be used together. The content of the inorganic fillerto be reused is not particularly limited, but it is from 2 to 80% byweight, and preferably from 5 to 60% by weight, based on the totalamount of the novel thermosetting resin molding material.

When the recovered product of the inorganic filler is used together withother chemical raw material, the chemical raw material to be usedtogether is not particularly limited, and examples thereof includeresins such as a novolac phenol resin, a resol type phenol resin, anepoxy resin, a melamine resin, an urea resin and the like. Furthermore,the chemical raw material obtained in the first embodiment may be used.

Furthermore, when the recovered product of the inorganic filler is usedas a raw material of the thermosetting resin molding material togetherwith an ordinary filler, the filler to be used together is notparticularly limited, but an inorganic base material and/or an organicbase material that is used in an ordinary thermosetting resin moldingmaterial may be used as a filler. Examples of the inorganic basematerial include glass fiber, calcium carbonate, calcined clay, talc,silica, diatomaceous earth, alumina, magnesium oxide and the like. Theinorganic base materials may be selected depending on applications of amolded product or the like as necessary. Furthermore, examples of theorganic base material include wood flour, pulp, plywood powder, paperpulverized powder, cloth pulverized powder and the like.

Subsequently, an operational effect of the embodiment will be described.According to the embodiment, a relationship between the proportion ofthe number of molecules of the second monomer to the number of moleculesof the first monomer in a reaction system and the residual ratio of thepolymer material is acquired in advance, whereby the addition amount ofthe first monomer to be added to the polymer material is determinedbased on the acquired relationship, and the decomposition efficiency ofthe polymer material may be controlled. Accordingly, the inorganicfiller containing the unreacted resin component may be recovered, andthe environmental load can be reduced.

When the inorganic filler contained in the polymer material is recoveredand reused, and the amount of the resin component undecomposed is high,properties of the product obtained from reuse may be deteriorated. Onthe other hand, under the conditions with the high decomposition rate ofthe polymer material, it is difficult to obtain a chemical raw materialhaving a high molecular weight.

However, according to the method of the embodiment, the amount of thefirst monomer to be added to the polymer material is found in advance,so that the inorganic filler may be recovered to such a degree that canbe reused while decomposing the polymer material to the chemical rawmaterial having a desired molecular weight. Accordingly, both of theresin component and the inorganic filler constituting the polymermaterial may be effectively reused.

Third Embodiment

FIG. 7 is a flow chart illustrating a method for producing a recycledresin of the embodiment. In the method for producing a recycled resin,the recycled resin is produced by chemically decomposing a resincomponent composed of a first monomer and a second monomer in a mixtureof a polymer material containing a resin component with the firstmonomer or a derivative of the first monomer, and mixing the resincomponent decomposed with the second monomer or a derivative of thesecond monomer. The method comprises acquiring a relationship in advancebetween a proportion of number of molecules of the second monomer tonumber of molecules of the first monomer in a reaction system forproducing the recycled resin from the resin component decomposed and amolecular weight of the recycled resin (S401);

determining an addition amount of the second monomer or the derivativeof the second monomer to be added to the decomposed resin componentbased on the above-stated relationship (S402); and

mixing the second monomer or the derivative of the second monomer in theaddition amount determined with the resin component decomposed (S403).

Hereinafter, the embodiment will be described in detail.

[S401: Acquisition of a Relationship Between the Molar Ratio of theSecond Monomer to the First Monomer in a Reaction System and theMolecular Weight of the Recycled Resin]

In S401, first, the decomposition reaction of the polymer material asdescribed in the first or second embodiment is carried out, and then themolar ratio of the second monomer to the first monomer is determinedwith the addition of the second monomer in an arbitrary amount to theobtained chemical raw material. As the polymer material and the secondmonomer, those exemplified in the first embodiment may be used. Then,the chemical raw material and the second monomer are polymerized toproduce a recycled resin, and the molecular weight of the obtainedrecycled resin is measured by the use of gel permeation chromatography(GPC). As specific examples of measurement units and conditions at thattime, two of TSKgel GMHL and two of TSKgel G2000HL manufactured by Tosohare used as a separation column, tetrahydrofuran is used as an eluent, acalibration curve is obtained in terms of polystyrene, a differentialrefractive index meter is used as a detector, a flow rate is set to 1cm³/min, and a temperature is set to 40° C. Next, the proportion of thenumber of molecules of the second monomer to the number of molecules ofthe first monomer in the reaction system is plotted on the transverseaxis, while the molecular weight of the recycled resin produced isplotted on the vertical axis. The molecular weight plotted on thevertical axis may be the number average molecular weight (Mn) or theweight average molecular weight (Mw). In this way, data on a specificcorrelation between the proportion of the number of molecules of thesecond monomer to the number of molecules of the first monomer and themolecular weight of the recycled resin produced may be acquired.

The molecular weight (Mw) of the chemical raw material used in theproduction method of the embodiment is preferably in the range of2.0×10² or more and 2.5×10³ or less. This molecular weight, in case ofthe phenol resin, corresponds to 2 to 25 nuclei. More preferably, themolecular weight is in the range of 2.0×10² or more and 1.5×10³ or less,and this molecular weight, in case of the phenol resin, corresponds to 2to 15 nuclei. The molecular weight distribution (Mw/Mn) is preferably inthe range of 1.0 or more and 3.0 or less, and more preferably in therange of 1.0 or more and 2.0 or less. In the embodiment, the term“molecular weight of the chemical raw material” refers to a molecularweight of the resin component in which the resin component contained inthe chemical raw material is contained in an amount of not less than 50%by weight.

Furthermore, the recycled resin obtained by the production method of theembodiment has a molecular weight (Mw) of usually 2.0×10² or more and1.0×10⁵ or less, and has a molecular weight distribution (Mw/Mn)preferably in the range of 2.0 or more and 15 or less, and morepreferably in the range of 3.0 or more and 10 or less. In theembodiment, the term “molecular weight of the recycled resin” refers toa molecular weight of the resin component in which the resin componentcontained in the recycled resin is contained in an amount of not lessthan 50% by weight.

[S402: Determination of the Addition Amount of the Second Monomer]

Subsequently, in S402, the proportion corresponding to the molecularweight of the recycled resin produced from the relationship obtained inS401 is selected. In this way, the addition amount of the second monomeror the derivative of the second monomer to be added to the decomposedresin component is determined. Specifically, the range of the targetmolecular weight of the recycled resin is determined in advance from theproportion of the mole numbers of the second monomer to the number ofmolecules of the first monomer of the chemical raw material. Then, therange of the proportion of the number of molecules of the second monomerto the number of the first monomer is determined, and according to thedetermined range, the amount of the second monomer is determined.Incidentally, in S401, the molecular weight of the recycled resincorresponding to arbitrary two points may be examined in the ranges inwhich the proportion of the number of molecules of the second monomer tothe number of molecules of the first monomer in a reaction system has acorrelation with the molecular weight of the recycled resin. At thistime, in S402, the addition amount of the second monomer to be added isdetermined from the above proportion and the molecular weight of thechemical raw material supplementing the obtained two points.

[S403: Mixing of the Second Monomer with the Chemical Raw Material]

Subsequently, as described in the first or second embodiment, thechemical decomposition reaction of the resin component contained in thepolymer material is carried out, and then the second monomer or thederivative of the second monomer in the addition amount determined inS402 is added to and mixed with the obtained chemical raw material. Atthis time, the chemical raw material is separated from the reactionmixture after the decomposition reaction, and then the second monomer orthe derivative of the second monomer may be added, or the second monomeror the derivative of the second monomer may be added to the mixture asit is without separation.

[S404: Obtaining the Recycled Resin]

Processing conditions for the mixture of the second monomer with thechemical raw material obtained in S403 may be controlled mainly by atemperature and pressure. The temperature is usually not less than 100°C., preferably not more than the temperature in the aforementioneddecomposition reaction, and more preferably 150° C. or more and 200° C.or less. In this way, the reaction may be carried out at a high rapidmolecular rate while suppressing acceleration of gelation of therecycled resin component.

Furthermore, the pressure is usually preferably atmospheric pressure ormore, not more than the pressure in the aforementioned decompositionreaction, and more preferably atmospheric pressure or more and 20 MPa orless. In this way, maintenance of a high molecular rate to an extentthat does not cause the gelation and the suppression of the energyconsumption are excellently balanced.

Meanwhile, the atmosphere is not particularly restricted, and any of airatmosphere or inert gas atmosphere such as nitrogen or the like may beselected, and any of an open system or a closed system may be used.Furthermore, the processing time may be controlled in the range of 1 to60 minutes and may be usually preferably set to about 3 to 30 minutes.

Also, in the embodiment, there is obtained a recycled resin having thesame chemical structure as that of the recycled resin described in thefirst embodiment.

The recycled resin, after a solvent, a residue and the like areseparated by the separation method described in the first embodiment,may be reused as a raw material of the recycled resin composition.

Furthermore, in the obtained recycled resin, other than a resincomponent having a target molecular weight, a reaction solvent such as afirst monomer or a second monomer, water and the like may be containedin a small amount.

As a method for producing a recycled resin composition, the recycledresin may be mixed with other raw material to produce the composition bya known production method. At this time, however, the recycled resinalone may be used as a raw material without using a novel raw material(virgin product), or may be used together with a virgin product and/or afiller. The content of the recycled resin is not particularly limited,but it is 2 to 80% by weight and preferably 5 to 60% by weight, based onthe total amount of the recycled resin composition.

When the recycled resin is used together with other chemical rawmaterial to produce the recycled resin composition, the chemical rawmaterial to be used together is not particularly limited, and examplesthereof include a novolac type phenol resin, a resol type phenol resin,an epoxy resin, a melamine resin and a urea resin.

Herein, when, for example, a novolac type phenol resin is used as therecycled resin, and the novolac type phenol resin is used together as aresin that is the other chemical raw material, usually,hexamethylenetetramine is used as a curing agent. The content ofhexamethylenetetramine is preferably 10 to 25 parts by weight, based on100 parts by weight in total of the recycled resin and the novolac typephenol resin, in the same manner as an ordinary polymer material. Thetotal content of the recycled resin and the novolac type phenol resin ispreferably 20 to 80% by weight and more preferably 30 to 60% by weight,based on the total amount of the recycled resin composition, even whenhexamethylenetetramine is used as a curing agent. Furthermore, in orderto control the curing rate, magnesium oxide, calcium hydroxide and thelike may be used as a curing auxiliary agent as necessary.

According to the method of the embodiment, the derivative of the secondmonomer in place of the second monomer may be added to the chemical rawmaterial to obtain a recycled resin. A resin different from the polymermaterial subjected to decomposition processing may be produced by usingthe thus-obtained recycled resin.

Subsequently, an operational effect of the embodiment will be described.According to the embodiment, a relationship between the proportion ofthe number of molecules of the second monomer to the number of moleculesof the first monomer in a reaction system and the molecular weight ofthe recycled resin produced in the reaction system is previouslyacquired, whereby the addition amount of the second monomer to be addedto the decomposition product of the resin component composed of a firstmonomer and a second monomer is determined based on the acquiredrelationship, and then the second monomer in an appropriate amount ismixed with the decomposed resin component in order to obtain a recycledresin having physical property to be desired. In this way, the recycledresin may be produced using the second monomer of a requisite minimumamount. Accordingly, the yield rate of the recycled resin may beimproved, and the environmental load may be reduced.

As described above, embodiments of the present invention have beenillustrated with reference to the drawings. However, these embodimentsare examples of the present invention, and various other constructionsmay also be employed.

For example, in the third embodiment, there is exemplified a method ofacquiring a relationship in advance between the proportion of the numberof molecules of the second monomer to the number of molecules of thefirst monomer in a reaction system and the molecular weight of therecycled resin produced in the reaction system. However, therelationship between the proportion and the physical property of therecycled resin in terms of the molecular weight may be acquired inadvance.

Furthermore, there may be employed a method comprising observing thephysical property reflecting the molecular weight of the recycled resinproduced in the reaction system with the addition of the second monomerto the reaction system for producing the recycled resin from thedecomposed resin component, without acquiring a relationship in advancebetween the proportion of the number of molecules of the second monomerto the number of molecules of the first monomer in the reaction systemand the physical property of the recycled resin produced in the reactionsystem.

For the purpose of increasing the accuracy, there may be employed amethod comprising acquiring a relationship in advance between theproportion of the number of molecules of the second monomer to thenumber of molecules of the first monomer in a reaction system and thephysical property of the recycled resin produced in the reaction system,and observing the physical property reflecting the molecular weight ofthe recycled resin produced in the reaction system with the addition ofthe second monomer to the reaction system for producing the recycledresin from the decomposed resin component.

Specifically, as shown in FIG. 8, a target molecular weight of therecycled resin is set (S501), and the second monomer is added to thereaction system for producing the recycled resin from the decomposedresin component (S502). That is, as described in the first or secondembodiment, the chemical decomposition reaction of the resin componentcontained in the polymer material is carried out, and the second monomeris added to the obtained chemical raw material. Here, the additionamount of the second monomer to be added may be determined by conductingS401 and S402 explained in the third embodiment. As the polymer materialand the second monomer, those explained in the first embodiment areused.

Subsequently, the physical property reflecting the molecular weight ofthe recycled resin produced in the reaction system are observed (S503),and then a relationship between the proportion of the number ofmolecules of the second monomer to the number of molecules of the firstmonomer in the reaction system and the physical property is acquired(S504). Subsequently, it is determined whether the molecular weight ofthe recycled resin reaches a target molecular weight (S505). When themolecular weight fails to reach the target (S505 No), the additionamount of the second monomer or the derivative of the second monomer tobe added to the decomposed resin component is redetermined based on theacquired relationship (S506). In S506, the proportion of the number ofmolecules of the second monomer to the number of molecules of the firstmonomer is selected from the physical property corresponding to thetarget molecular weight of the recycled resin, and then the additionamount of the second monomer corresponding to the chemical raw materialis determined. Subsequently, the second monomer in the determined amountis added to the reaction system and mixed. In this way, a recycled resinhaving a desired molecular weight may be obtained (S505 Yes, S507).

The physical property may be measured values obtained by one or moremethods selected from any of a method for measuring physical property, amethod for separation and analysis, spectrum analysis, electromagneticanalysis and thermal analysis.

The method for measuring physical property refers to a method ofmeasuring viscosity, specific gravity, melting point, pH, solubility,particle size and the like. The method for separation and analysisrefers to a gas chromatography method, a gel permeation chromatographymethod, an ion chromatography method, a liquid chromatography method andthe like. Spectrum analysis refers to a light scattering method, aninfrared absorption method and an ultraviolet absorption method.Electromagnetic analysis refers to a nuclear magnetic resonance (NMR)method, a mass spectrometry (MS) method and the like. Thermal analysisrefers to a thermogravimetric method and a differential thermal analysismethod.

According to the above method, while the second monomer of a requisiteminimum amount is mixed with the decomposed resin component, therecycled resin may be produced. Accordingly, the yield rate of therecycled resin may be improved, and the environmental load may bereduced.

EXAMPLES Example 1

Hereinafter, the first invention will be illustrated in detail referringto FIG. 1 by way of Example. However, the present invention is notrestricted to the Example.

[S101: Acquisition of Data on a Relationship Between the Proportion ofthe Number of Molecules of the Second Monomer to the Number of Moleculesof the First Monomer in a Reaction System and the Molecular Weight ofthe Chemical Raw Material Produced in the Reaction System]

As a polymer material, one obtained by pulverizing a cured product of aglass fiber-reinforced phenol resin molding material (glass fiber: about60% contained), followed by classifying to a particle diameter of notmore than 250 μm was used. In the polymer material, a first monomer(monomer A in Table 1) was phenol, and a second monomer (monomer B inTable 1) was formaldehyde. As the content of each monomer per 1 g of thepolymer material, the content of the first monomer was 3.3×10⁻³ mole/gand the content of the second monomer was 5.5×10⁻³ mole/g.

Here, the phenol resin was formed with a plurality of groups composed ofa hydroxyphenylene group and a methylene group bonded thereto. Thenumber of hydroxyphenylene groups constituting the phenol resin wasconverted as the number of molecules of the first monomer, while thenumber of methylene groups constituting the phenol resin was convertedas the number of molecules of the second monomer.

When the above polymer material was added to a mixture of the firstmonomer with water, powdery calcium hydroxide was added as a basecatalyst. The amounts of respective reagents in use are shown inTable 1. The resulting mixture was introduced into an autoclave(internal volume: 200 cm³, a product of Nitto Kouatsu Co., Ltd.), andthen heated while stirring at a rate of 300 rpm to have an internaltemperature of 260° C., whereby the internal pressure in the reactor wasincreased up to 3.5 MPa and maintained for 30 minutes to carry outdecomposition processing.

TABLE 1 Number of molecules to be introduced Weight to be introducedPhenol Phenol Formaldehyde Catalyst (Polymer material) (Reactionsolvent) Phenol (Polymer material) Polymer Reaction solvent CalciumMonomer A Monomer A Monomer A Monomer B material Phenol Water hydroxide({circle around (1)}) ({circle around (2)}) ({circle around (3)} ={circle around (1)} + {circle around (2)}) ({circle around (4)}) [g] [g][g] [g] [mol] [mol] [mol] [mol] 1-1 87.4 85.6 21.3 0.9 0.29 0.91 1.200.48 1-2 58.3 85.6 21.3 0.6 0.19 0.91 1.10 0.32 1-3 26.7 85.6 21.3 0.30.09 0.91 1.00 0.15 1-4 12.0 85.6 21.3 0.1 0.04 0.91 0.95 0.07 1-5 87.463.0 43.9 0.9 0.29 0.67 0.96 0.48 1-6 87.4 55.0 51.9 0.9 0.29 0.59 0.870.48 1-7 87.4 15.0 91.9 0.9 0.29 0.16 0.45 0.48 1-8 87.4 0.0 106.9 0.90.29 0.00 0.29 0.48 Decomposition results Molar ratio to be introducedDecomposition Yield of Formaldehyde/Phenol rate of Molecular weight ofchemical chemical Monomer B/Monomer A polymer raw material raw (={circlearound (4)}/{circle around (3)}) material Mn Mw material [—] [wt %] [—][—] [g] 1-1 0.40 100 478 700 99 1-2 0.29 100 418 560 66 1-3 0.15 100 401565 30 1-4 0.07 100 390 571 13 1-5 0.50 95 673 1865 94 1-6 0.55 90 7532881 89 1-7 1.07 5 Unmeasurable Unmeasurable 4 1-8 1.67 5 UnmeasurableUnmeasurable 4

The decomposition rate of the polymer material was evaluated in thefollowing procedure. The product after the decomposition processing wasdissolved in and diluted with tetrahydrofuran (hereinafter referred toas THF), and then filtered with a filter of 1.0 μm. A THF-insolubleresidue remained in the filter was dried at 100° C. for 12 hours andthen weighed, the weight loss corresponding to the weight of theintroduced polymer material was evaluated, and the decomposition rate ofthe polymer material was evaluated using the following Formulae 2 to 5.The decomposition rate was 100%.Decomposition rate[%]={weight loss (g)/amount (g) of resin component ofpolymer material}×100  Formula 2Weight loss=weight (g) of introduced polymer material−weight (g) ofTHF-insoluble residue  Formula 3Amount of resin component of polymer material=weight (g) of introducedpolymer material−(weight (g) of glass fiber in introduced polymermaterial)  Formula 4Weight of glass fiber in introduced polymer material=weight (g) ofintroduced polymer material×0.6  Formula 5

The recovered product after the decomposition processing was measured bythe use of gel permeation chromatography (GPC). At this time, two ofTSKgel GMHL and two of TSKgel G2000HL manufactured by Tosoh were used asa separation column, THF was used as an eluent, a calibration curve wasobtained in terms of polystyrene, a differential refractive index meterwas used as a detector, a flow rate was set to 1 cm³/min, and atemperature was set to 40° C. Further, the molecular weight of thechemical raw material was calculated as the number average molecularweight and the weight average molecular weight by analyzing the chartobtained by GPC analysis excluding the peak of the first monomer(phenol).

As a result, under the condition with the molar ratio of the secondmonomer to the first monomer of smaller than 1, the decomposition rateof the polymer material was high, i.e., not less than 90%. On the otherhand, under the condition with the molar ratio of the second monomer tothe first monomer of greater than 1, the decomposition rate of thepolymer material was extremely low, i.e., about 5%, so that thedecomposition processing hardly proceeded. When the molar ratio of thesecond monomer to the first monomer was greater than 1, it was unable tomeasure the molecular weight from the recovered product after thedecomposition processing by the GPC analysis.

FIGS. 9 and 10 each illustrate a relationship between the molar ratio ofthe second monomer to the first monomer and the molecular weight of thechemical raw material obtained from the measurement results of GPC. InFIGS. 9 and 10, the molar ratio of the second monomer to the firstmonomer in the reaction system is plotted on the transverse axis. InFIG. 9, the number average molecular weight (Mn) of the chemical rawmaterial obtained from the measurement results of GPC is plotted on thevertical axis. In FIG. 10, the weight average molecular weight (Mw) ofthe chemical raw material obtained from the measurement results of GPCis plotted on the vertical axis.

From FIGS. 9 and 10, it is found that, as the molar ratio of the secondmonomer to the first monomer is smaller, the molecular weight of thechemical raw material becomes smaller. That is, if a relationshipdiagram is substantially found before the decomposition processing iscarried out, the molecular weight of the chemical raw material to berecovered can be controlled by adjusting the molar ratio of the secondmonomer to the first monomer. Similarly, it is found that, from FIGS. 9and 10, although the molar ratio of the second monomer to the firstmonomer is made small, a chemical raw material having a smallermolecular weight than a certain predetermined value (threshold) may notbe recovered. From this fact, when the chemical raw material having alow molecular weight is recovered, the molar ratio of the second monomerto the first monomer may be made small, i.e., a requisite minimumamount, by obtaining a threshold, that is, the polymer material may behighly effectively decomposed with the addition of the first monomer inan appropriate amount.

[S102: Determination of the Addition Amount of the First Monomer to beAdded to the Polymer Material]

An approximate curve 1 was obtained, as shown in FIG. 9( b), from dataof 1-1, 1-5 and 1-6 in Table 1 among data shown in Table 1 and FIG. 9(a). An approximate expression of the approximate curve 1 wasy=1.9×10³×−2.6×10². Furthermore, an approximate curve 2 was obtainedfrom data of 1-2, 1-3 and 1-4. An approximate expression wasy=1.3×10²×+3.8×10². A threshold of the molar ratio of the second monomerto the first monomer was obtained from a point where the approximatecurve 1 crossed the approximate curve 2. Similarly, approximate curves 3and 4 were obtained, as shown in FIG. 10( b), from data shown in Table 1and FIG. 10( a). A threshold of the molar ratio of the second monomer tothe first monomer was obtained. As a result, 0.4 of a threshold wasobtained.

Next, as a polymer material, 87.4 g of the polymer material used in S101was prepared. 0.91 mole of phenol was decided to be added from the factsthat the amount of phenol (monomer A) constituting the polymer materialwas 0.29 mole and the amount of formaldehyde (monomer B) was 0.48 mole.

[S103: Mixing of the First Monomer with the Polymer Material]

To a mixture of 0.91 mole of phenol with 21.3 g of water was added 87.4g of the polymer material. At this time, 0.9 g of powdery calciumhydroxide was added as a base catalyst.

[S104: Making the First Monomer into a Supercritical State orSubcritical State]

The mixture obtained in S103 was introduced into an autoclave (internalvolume: 200 cm³, a product of Nitto Kouatsu Co., Ltd.), and then heatedwhile stirring at a rate of 300 rpm to have an internal temperature of260° C., whereby the internal pressure in the reactor was increased upto 3.5 MPa and maintained for 30 minutes to carry out decompositionprocessing.

[S105: Obtaining the Chemical Raw Material]

The recovered product after the decomposition processing was measured bythe use of GPC in the same manner as in S101. As a result, it was foundthat a chemical raw material having a number average molecular weight(Mn) of 478 and a weight average molecular weight (Mw) of 700 wasproduced.

Subsequently, a recycled resin was produced from the chemical rawmaterial produced in S105.

Evaluation 1-1

To the recovered product after the decomposition processing was added 18g of an aqueous solution of formalin (formaldehyde: 43% contained) as amulti-functional compound. The resulting mixture was heated whilestirring at a rate of 300 rpm to have an internal temperature of 220°C., whereby the internal pressure in the reactor was increased up to 2MPa and maintained for 20 minutes to carry out a reaction with themulti-functional compound. Subsequently, the product after thedecomposition processing was dissolved in and diluted with methanol, andthen filtered with a filter of 1.0 μm to recover a filtrate. Thefiltrate was heated under ordinary pressure or reduced pressure, wherebyvolatile components such as methanol, a reaction solvent (water, phenol)and the like were evaporated to recover a recycled resin as anonvolatile component. The resulting recycled resin was analyzed by GPCin the same manner as in S101 to evaluate the molecular weight. As forthe molecular weight of the resulting recycled resin, the number averagemolecular weight (Mn) was 914, while the weight average molecular weight(Mw) was 4,658.

Evaluation 1-2

The decomposition processing of a glass fiber-reinforced phenol resinmolding material and the reaction with a multi-functional compound wereconducted in the same procedure as in Evaluation 1-1, except that 21 gof an aqueous solution of formalin (formaldehyde: 43% contained) wasadded as a multi-functional compound. As for the molecular weight of theresulting recycled resin, the number average molecular weight (Mn) was995, while the weight average molecular weight (Mw) was 7,289.

Evaluation 1-3

The decomposition processing of a glass fiber-reinforced phenol resinmolding material and the reaction with a multi-functional compound wereconducted in the same manner as in Evaluation 1-1, except that 27 g ofan aqueous solution of formalin (formaldehyde: 43% contained) was addedas a multi-functional compound. As for the molecular weight of theresulting recycled resin, the number average molecular weight (Mn) was1,071, while the weight average molecular weight (Mw) was 14,967.

From the above results, the molecular weights of the recycled resinswere excellent. Furthermore, it was found that the gel time, bendingstrength and bending elastic modulus were equal to the conventionalones, and the recycled resins having a quality comparable toconventional recycled resins were obtained.

Example 2

Furthermore, the third invention will be illustrated in detail referringto FIG. 5 by way of Example. However, the present invention is notrestricted to the Example.

[S301: Decomposition Processing of the Polymer Material]

As a polymer material, one obtained by pulverizing a cured product of aglass fiber-reinforced phenol resin molding material (glass fiber: about60% contained), followed by classifying to a particle diameter of notmore than 250 μm was used. In the polymer material, a first monomer(monomer A) was phenol, and a second monomer (monomer B) wasformaldehyde. As for the content of each monomer per 1 g of the polymermaterial, the content of the first monomer was 3.3×10⁻³ mole/g and thecontent of the second monomer was 5.5×10⁻³ mole/g.

Here, the phenol resin was formed with a plurality of groups composed ofa hydroxyphenylene group and a methylene group bonded thereto. Thenumber of hydroxyphenylene groups constituting the phenol resin wasconverted as the number of molecules of the first monomer, while thenumber of methylene groups constituting the phenol resin was convertedas the number of molecules of the second monomer.

When the above polymer material was added to a mixture of the firstmonomer with water, powdery calcium hydroxide was added as a basecatalyst. The amounts of respective reagents in use are shown in Table2. The resulting mixture was introduced into an autoclave (internalvolume: 200 cm³, a product of Nitto Kouatsu Co., Ltd.), and then heatedwhile stirring at a rate of 300 rpm to have an internal temperature of260° C., whereby the internal pressure in the reactor was increased upto 3.5 MPa and maintained for 30 minutes to carry out decompositionprocessing.

TABLE 2 Number of molecules to be introduced Phenol Phenol FormaldehydeWeight to be introduced (Polymer (Reaction (Polymer Catalyst material)solvent) Phenol material) Polymer Reaction solvent Calcium Monomer AMonomer A Monomer A Monomer B material Phenol Water hydroxide ({circlearound (1)}) ({circle around (2)}) ({circle around (3)} = {circle around(1)} + {circle around (2)}) ({circle around (4)}) [g] [g] [g] [g] [mol][mol] [mol] [mol] 2-1 87.4 85.6 21.3 0.9 0.29 0.91 1.20 0.48 2-2 58.385.6 21.3 0.6 0.19 0.91 1.10 0.32 2-3 26.7 85.6 21.3 0.3 0.09 0.91 1.000.15 2-4 12.0 85.6 21.3 0.1 0.04 0.91 0.95 0.07 2-5 87.4 65.0 41.9 0.90.29 0.69 0.98 0.48 2-6 87.4 63.0 43.9 0.9 0.29 0.67 0.96 0.48 2-7 87.458.0 48.9 0.9 0.29 0.62 0.91 0.48 2-8 87.4 55.0 51.9 0.9 0.29 0.59 0.870.48 2-9 87.4 15.0 91.9 0.9 0.29 0.16 0.45 0.48 2-10 87.4 0.0 106.9 0.90.29 0.00 0.29 0.48 Residual ratio of Molar ratio to be introduced Yieldof resin component Formaldehyde/Phenol Molecular weight of chemicalchemical contained in Monomer B/Monomer A raw material raw inorganicfiller (={circle around (4)}/{circle around (3)}) Mn Mw materialrecovered product [—] [—] [—] [g] [wt %] 2-1 0.40 478 700 99 0 2-2 0.29418 560 66 0 2-3 0.15 401 565 30 0 2-4 0.07 390 571 13 0 2-5 0.49 6111215 95 4 2-6 0.50 673 1865 94 5 2-7 0.53 721 2535 91 8 2-8 0.55 7532881 89 10 2-9 1.07 Unmeasurable Unmeasurable 4 95 2-10 1.67Unmeasurable Unmeasurable 4 95

[S302: Evaluation of the Residual Ratio of the Undecomposed ResinComponent]

The residual ratio of the unreacted resin component was evaluated in thefollowing procedure. The product after the decomposition processing wasdissolved in and diluted with THF, and then filtered with a filter of1.0 μm. A THF-insoluble content remained in the filter was dried at 100°C. for 12 hours and then weighed. The dried THF-insoluble residue wastaken as an inorganic filler recovered product (1). Under the conditionsof 5 hour/500° C., the inorganic filler recovered product (1) wassubjected to an incineration treatment, whereby a residue (2) afterincineration was obtained, and the residual ratio of the unreacted resincomponent contained in the inorganic filler recovered product (1) wascalculated using the Formula 1 illustrated in the second embodiment.

Furthermore, the THF-soluble matter was measured by the use of gelpermeation chromatography (GPC). At this time, two of TSKgel GMHL andtwo of TSKgel G2000HL manufactured by Tosoh were used as a separationcolumn, THF was used as an eluent, a calibration curve was obtained interms of polystyrene, a differential refractive index meter was used asa detector, a flow rate was set to 1 cm³/min, and a temperature was setto 40° C. Further, the molecular weight of the chemical raw materialcontaining the decomposed resin component was obtained by analyzing thechart obtained by GPC analysis excluding the peak of the first monomer(phenol).

[S303: Acquisition of Data on a Relationship Between the Proportion ofthe Number of Molecules of the Second Monomer to the Number of Moleculesof the First Monomer in a Reaction System and the Residual Ratio of theUndecomposed Resin Component]

FIG. 11 illustrates a relationship between the molar ratio of the secondmonomer to the first monomer and the residual ratio of the unreactedresin component contained in the inorganic filler recovered product.From FIG. 11, it is found that, as the molar ratio of the second monomerto the first monomer is smaller, the residual ratio becomes smaller.That is, if a relationship diagram is substantially found before thedecomposition processing is carried out, the residual ratio of theunreacted resin component contained in the inorganic filler recoveredproduct may be controlled by adjusting the molar ratio of the secondmonomer to the first monomer. Similarly, it is found that, from FIG. 11,when the molar ratio of the second monomer to the first monomer is madesmall, the residual ratio reaches 0% from a certain predetermined value(threshold). From this fact, it is found that the first monomer in anappropriate amount may be added by obtaining a threshold, anddecomposition processing of the polymer material may be carried outhighly effectively.

[S304: Determination of the Addition Amount of the First Monomer to beAdded to the Polymer Material]

From data shown in Table 2 and FIG. 11, the first monomer was added suchthat the residual ratio of the unreacted resin component was 2, 4, 5, 8and 10%, that is, 87.4 g of the polymer material used in S301 wasprepared as a polymer material. 0.73, 0.69, 0.67, 0.62 and 0.59 mole ofphenol were decided to be added respectively from the facts that theamount of phenol (first monomer) constituting the polymer material was0.29 mole and the amount of formaldehyde (second monomer) was 0.48 mole.

[S305: Mixing of the First Monomer with the Polymer Material]

To a mixture of 0.69 mole of phenol with 41.9 g of water was added 87.4g of the above polymer material. At this time, 0.9 g of powdery calciumhydroxide was added as a base catalyst to give Example 2-A. Further, toa mixture of 0.67 mole of phenol with 43.9 g of water was added 87.4 gof the above polymer material. At this time, 0.9 g of powdery calciumhydroxide was added as a base catalyst to give Example 2-B. To a mixtureof 0.62 mole of phenol with 48.9 g of water was added 87.4 g of theabove polymer material. At this time, 0.9 g of powdery calcium hydroxidewas added as a base catalyst to give Example 2-C. To a mixture of 0.59mole of phenol with 51.9 g of water was added 87.4 g of the abovepolymer material. At this time, 0.9 g of powdery calcium hydroxide wasadded as a base catalyst to give Example 2-D. To a mixture of 0.73 moleof phenol with 38.3 g of water was added 87.4 g of the above polymermaterial. At this time, 0.9 g of powdery calcium hydroxide was added asa base catalyst to give Example 2-E. In Examples 2-A and 2-B, n was 2.In Example 2-E, n was 3. In other Examples, n was 1. The mixtures ofrespective Examples obtained in S305 were introduced into an autoclave(internal volume: 200 cm³, a product of Nitto Kouatsu Co., Ltd.), andthen heated while stirring at a rate of 300 rpm to have an internaltemperature of 260° C., whereby the internal pressure in the reactor wasincreased up to 3.5 MPa and maintained for 30 minutes to carry outdecomposition processing.

[S306: Recovery of the Inorganic Filler]

The product after the decomposition processing was dissolved in anddiluted with tetrahydrofuran (hereinafter referred to as THF), and thenfiltered with a filter of 1.0 μm. A THF-insoluble content remained inthe filter was dried at 100° C. for 12 hours and then weighed. The driedTHF-insoluble residue was taken as an inorganic filler recoveredproduct. The residual ratio of the unreacted resin component containedin the obtained inorganic filler recovered product was examined in themethod shown in S302 and as a result, the residual ratio of Example 2-Awas 4%, the residual ratio of Example 2-B was 5%, the residual ratio ofExample 2-C was 8%, the residual ratio of Example 2-D was 10%, and theresidual ratio of Example 2-E was 2%.

Evaluation 2-1

Subsequently, a molding material was produced using the inorganic fillerrecovered in S306. The properties of the molding material obtained byreusing the inorganic filler recovered in Examples 2-A, 2-B, 2-C and 2-Das a raw material were evaluated. A molding material composed of aninorganic filler recovered product (10%), a glass fiber (50%), and aphenol novolac resin and hexamethylenetetramine (40% in total) wasadjusted to obtain a test piece using a transfer molding machine underthe curing conditions of 3 min/175° C. In accordance with a test methodof JIS K 6911, the bending strength of the test piece was evaluated. Forthe purpose of comparison, a virgin molding material was prepared. Thatis, without employing the inorganic filler recovered product, a moldingmaterial composed of a glass fiber (60%), and a phenol novolac resin andhexamethylenetetramine (40% in total) was prepared, and the bendingstrength was evaluated in the same manner. The results are shown inTable 3.

TABLE 3 Residual ratio of resin Mixing ratio of inorganic fillercomponent contained in recovered product used in Strength of moldingInorganic filler inorganic filler recovered production of moldingmaterial (bending strength) recovered product product % material % MPaRemarks Example 2-A 4 10 210 Average value (n = 2) Example 2-B 5 10 203Average value (n = 2) Example 2-C 8 10 182 — Example 2-D 10 10 158 —Example 2-E 2 20 207 — 2 30 198 — 2 60 141 — Comparative 0 208 Averagevalue (n = 8), Example (virgin Maximum: 214, Minimum: 198 material)

As shown in Table 3, for all of the residual ratios of the unreactedresin components contained in the inorganic filler recovered products of4, 5, 8 and 10%, the results comparable to those of the virgin moldingmaterial of the comparison were obtained.

Evaluation 2-2

Furthermore, the properties of the molding material obtained by reusingthe inorganic filler recovered in Example 2-E as a raw material wereevaluated. A molding material A composed of an inorganic fillerrecovered product (20%), a glass fiber (40%), and a phenol novolac resinand hexamethylenetetramine (40% in total), a molding material B composedof an inorganic filler recovered product (30%), a glass fiber (30%), anda phenol novolac resin and hexamethylenetetramine (40% in total), and amolding material C composed of an inorganic filler recovered product(60%), and a phenol novolac resin and hexamethylenetetramine (40% intotal) were respectively adjusted to obtain a test piece using atransfer molding machine under the curing conditions of 3 min/175° C. Inaccordance with a test method of JIS K 6911, the bending strength of thetest piece was evaluated. For the purpose of comparison, a virginmolding material was prepared. That is, without employing the inorganicfiller recovered product, a molding material composed of a glass fiber(60%), and a phenol novolac resin and hexamethylenetetramine (40% intotal) was prepared, and the bending strength was evaluated in the samemanner. The results are shown in Table 3.

As shown in Table 3, when the residual ratio of the unreacted resincomponent contained in the inorganic filler recovered product was 2%,although the amount of the inorganic filler recovered product to bemixed was equal to the amount of the glass fiber of the virgin product,the results of the recycled molding material comparable to those of thevirgin molding material were obtained.

Example 3

Furthermore, the second invention will be illustrated in detailreferring to FIG. 7 by way of Example. However, the present invention isnot restricted to the Example.

[S401: Acquisition of Data on a Relationship Between the Proportion ofthe Number of Molecules of the Second Monomer to the Number of Moleculesof the First Monomer in a Reaction System and the Molecular Weight ofthe Recycled Resin]

To the decomposition product of 2-1 obtained in the above S301 was added18 g of an aqueous solution of formalin (formaldehyde: 43% contained) asa second monomer. The amounts of respective reagents used are shown inTable 4.

TABLE 4 Number of molecules to be introduced Phenol Phenol FormaldehydeFormaldehyde Weight to be introduced (Polymer (Reaction (Polymer(Molecular weight Catalyst Molecular material) solvent) Phenol material)adjust) Polymer Reaction solvent Calcium weight adjust Monomer A MonomerA Monomer A Monomer B Monomer B material Phenol Water hydroxide Formalin({circle around (1)}) ({circle around (2)}) ({circle around (3)} ={circle around (1)} + {circle around (2)}) ({circle around (4)})({circle around (5)}) [g] [g] [g] [g] [g] [mol] [mol] [mol] [mol] [mol]3-1 87.4 85.6 21.3 0.9 0.0 0.29 0.91 1.20 0.48 0.00 3-2 87.4 85.6 21.30.9 12.5 0.29 0.91 1.20 0.48 0.18 3-3 87.4 85.6 21.3 0.9 18.0 0.29 0.911.20 0.48 0.26 3-4 87.4 85.6 21.3 0.9 21.0 0.29 0.91 1.20 0.48 0.30 3-587.4 85.6 21.3 0.9 27.0 0.29 0.91 1.20 0.48 0.39 3-6 87.4 55.0 51.9 0.90.0 0.29 0.59 0.87 0.48 0.00 Number of molecules to be introduced Molarratio to be introduced Production results FormaldehydeFormaldehyde/Phenol Decomposition Molecular weight of regeneratedMonomer B Monomer B/Monomer A rate of polymer resin Yield of ({circlearound (6)} = {circle around (4)} + {circle around (5)}) (={circlearound (6)}/{circle around (3)}) material Mn Mw regenerated resin [mol][—] [wt %] [—] [—] [g] 3-1 0.48 0.40 100 478 700 99 3-2 0.66 0.55 100757 2898 144 3-3 0.74 0.62 100 914 4658 162 3-4 0.78 0.65 100 995 7289171 3-5 0.87 0.72 100 1071 14967 190 3-6 0.48 0.55 90 753 2881 89

The mixture was heated while stirring at a rate of 300 rpm to have aninternal temperature of 220° C., whereby the internal pressure in thereactor was increased up to 2 MPa and maintained for 20 minutes to carryout a reaction with a multi-functional compound. Subsequently, theproduct after the reaction was dissolved in and diluted with methanol,and then filtered with a filter of 1.0 μm to recover a filtrate. Thefiltrate was heated under ordinary pressure or reduced pressure, wherebyvolatile components such as methanol, a reaction solvent (water, phenol)and the like were evaporated to recover a recycled resin as anonvolatile component.

The recovered recycled resin was measured by the use of gel permeationchromatography (GPC). At this time, two of TSKgel GMHL and two of TSKgelG2000HL manufactured by Tosoh were used as a separation column, THF wasused as an eluent, a calibration curve was obtained in terms ofpolystyrene, a differential refractive index meter was used as adetector, a flow rate was set to 1 cm³/min, and a temperature was set toand 40° C. Further, the molecular weight of the recycled resin wascalculated by analyzing the chart obtained by GPC analysis excluding thepeak of the first monomer (phenol) added as a reaction solvent.

FIGS. 12 and 13 each illustrate a relationship between the molar ratioof the second monomer to the first monomer and the molecular weight ofthe recycled resin obtained from measurement results of GPC. In FIGS. 12and 13, the molar ratio of the second monomer to the first monomer in areaction system is plotted on the transverse axis. In FIG. 12, thenumber average molecular weight (Mn) of the recycled resin obtained frommeasurement results of GPC is plotted on the vertical axis. In FIG. 13,the weight average molecular weight (Mw) of the recycled resin obtainedfrom measurement results of GPC is plotted on the vertical axis.

From FIGS. 12 and 13, a relationship between the molar ratio of thesecond monomer to the first monomer and the molecular weight of therecycled resin may be found. That is, if a relationship diagram issubstantially found before the recycle processing is carried out, themolecular weight of the recycled resin may be controlled by adjustingthe molar ratio of the second monomer to the first monomer. From thisfact, the recycled resin may be highly effectively produced with theaddition of the second monomer in an appropriate amount.

[S402: Determination of the Addition Amount of the Second Monomer to beAdded to the Chemical Raw Material]

Example 3-A

It was considered that a recycled resin having Mn of 9.1×10² and Mw of4.7×10³ was obtained. Referring to Table 4, FIG. 12 and FIG. 13 obtainedin S401, the molar ratio of the second monomer to the first monomer was0.62.

Example 3-B

It was considered that a recycled resin having Mn of 1.0×10³ and Mw of7.3×10³ was obtained. Referring to Table 4, FIG. 12 and FIG. 13 obtainedin S401, the molar ratio of the second monomer to the first monomer was0.65.

Example 3-C

It was considered that a recycled resin having Mn of 1.1×10³ and Mw of1.5×10⁴ was obtained. Referring to Table 4, FIG. 12 and FIG. 13 obtainedin S401, the molar ratio of the second monomer to the first monomer was0.72.

[S403: Mixing of the Second Monomer with the Chemical Raw Material]

With respect to Example 3-A, to the decomposition product of 2-1 shownin Table 2 was added 18 g of an aqueous solution of formalin(formaldehyde: 43% contained). With respect to Example 3-B, to thedecomposition product of 2-1 shown in Table 2 was added 21 g of anaqueous solution of formalin (formaldehyde: 43% contained). With respectto Example 3-C, to the decomposition product of 2-1 shown in Table 2 wasadded 27 g of an aqueous solution of formalin (formaldehyde: 43%contained). With respect to each Example, the mixture was heated whilestirring at a rate of 300 rpm to have an internal temperature of 220°C., whereby the internal pressure in the reactor was increased up to 2MPa and maintained for 20 minutes to carry out a reaction with thesecond monomer.

[S404: Obtaining the Recycled Resin]

With respect to respective Examples, the product after the reaction wasdissolved in and diluted with methanol, and then filtered with a filterof 1.0 μm to recover a filtrate. The filtrate was heated under ordinarypressure or reduced pressure, whereby volatile components such asmethanol, a reaction solvent (water, phenol) and the like wereevaporated to recover a recycled resin as a nonvolatile component. Theobtained recycled resin was analyzed by GPC in the same manner as inS401 to evaluate the molecular weight. As for the molecular weight ofthe obtained recycled resin, in Example 3-A, the number averagemolecular weight (Mn) was 913, and the weight average molecular weight(Mw) was 4,705. Furthermore, in Example 3-B, the number averagemolecular weight (Mn) was 1,015, and the weight average molecular weight(Mw) was 7,325. Furthermore, in Example 3-C, the number averagemolecular weight (Mn) was 1,092, and the weight average molecular weight(Mw) was 15,117.

From the above results, the molecular weights of the recycled resinswere excellent. Furthermore, it was found that the gel time, bendingstrength and bending elastic modulus were equal to the conventionalones, and the recycled resins having a quality comparable toconventional recycled resins were obtained.

Example 4

Furthermore, a modified example of the second invention will beillustrated in detail referring to FIG. 8 by way of Example. However,the present invention is not restricted to the Example.

As a recycled resin manufacturing apparatus, a pilot plant equipped witha raw material supply unit, a decomposition reaction unit, apolymerization reaction unit, a solid-liquid separation unit and anevaporation unit was used. The raw material supply unit is equipped witha diaphragm pump (a slurry supply unit) for supplying a slurry having amaximum discharge pressure of 15 MPa and a diaphragm pump (a formalinpump) for supplying formalin having a maximum discharge pressure of 15MPa. The decomposition reaction unit and the polymerization reactionunit are equipped with SUS316 tube type reactors having an internaldiameter of 16.7 mm. The solid-liquid separation unit is equipped with acentrifugal separator (decanter). The evaporation unit is equipped witha falling film type evaporator, and is equipped with a vibration typeviscometer (FVM80A-EXHT, a product of Sekonic Corporation) capable ofon-line measurement of the melt viscosity of the recycled resin obtainedin the downstream of the aforementioned evaporator. In this Example, theterm “physical properties reflecting the molecular weight of therecycled resin” refers to the melt viscosity measured at a frequency of1,000 Hz at 150° C. with the aforementioned vibration type viscometer.

First, a plurality of recycled resins having different molecular weightswere prepared, and the molecular weights were measured by the use of gelpermeation chromatography (GPC). The molecular weights of respectiverecycled resins were calculated with the same apparatus configuration,measurement conditions and analysis method as in Example 1.Subsequently, using the vibration type viscometer provided in theevaporation unit of the recycled resin manufacturing apparatus (pilotplant), the melt viscosity of the aforementioned recycled resin having adifferent molecular weight at 150° C. was evaluated. FIG. 14 illustratesthe weight average molecular weight (Mw) of the recycled resin evaluatedby GPC, and the melt viscosity of the recycled resin evaluated at afrequency of 1,000 Hz at 150° C. using the vibration type viscometer.The melt viscosity of the recycled resin was measured from therelational expression of this figure, so that its molecular weight maybe estimated.

[S501: Setting of the Target Molecular Weight of the Recycled Resin]

The target weight average molecular weight (Mw) of the recycled resinwas set to 3.0×10³, and a tolerance range of 2.7×10³ to 3.3×10³corresponding to ±10% of the target value was set.

[S502: Addition of the Second Monomer to the Chemical Raw Material]

As a polymer material, in the same manner as in Example 1, one obtainedby pulverizing a cured product of a glass fiber-reinforced phenol resinmolding material (glass fiber: about 60% contained), followed byclassifying to a particle diameter of not more than 250 μm was used. Inthe polymer material, a first monomer was phenol, and a second monomerwas formaldehyde. As for the content of each monomer per 1 g of thepolymer material, the content of the first monomer was 3.3×10⁻³ mole/gand the content of the second monomer was 5.5×10⁻³ mole/g.

A slurry comprising said polymer material of 34%, phenol of 55%, waterof 10% and calcium hydroxide of 1% was prepared. Using a slurry supplypump in the raw material supply unit of the recycled resin manufacturingapparatus (pilot plant), the aforementioned slurry was supplied to thedecomposition reaction unit at a flow rate of 158.4 kg/hr, and thenchemical decomposition processing of the resin component contained inthe polymer material was carried out. At this time, the reactiontemperature was 300° C. and the reaction pressure was 10 MPa.

Next, using a formalin supply pump, to the polymerization reaction unitin the downstream unit of the above-stated decomposition reaction unitwas supplied an aqueous solution of formalin (formaldehyde: 37%contained) as a second monomer at a flow rate of 14.7 kg/hr, and then itwas mixed with the product at the decomposition reaction unit to carryout the reaction. At this time, the reaction temperature was 170° C. andthe reaction pressure was 10 MPa. Subsequently, in the solid-liquidseparation unit, solid components contained in the product after thereaction were removed, and then in the evaporation unit, unreactedphenol and water were evaporated to recover a recycled resin.Incidentally, all of the aforementioned supply unit, the decompositionreaction unit, the polymerization reaction unit, the solid-liquidseparation unit and the evaporation unit were operated in a continuousflow process.

[S503: Observation of the Physical Properties Reflecting the MolecularWeight of the Recycled Resin]

In recovering the recycled resin continuously at the evaporation unit ofthe recycled resin manufacturing apparatus (pilot plant), using theequipped vibration type viscometer, the melt viscosity of the recycledresin at 150° C. was observed on line. The melt viscosity was 299 mPa·s.

[S504: Acquisition of a Relationship Between the Molar Ratio of theSecond Monomer to the First Monomer and the Molecular Weight of theRecycled Resin]

When a flow rate of the aqueous solution of formalin was 14.7 kg/hr, themolar ratio of formaldehyde to phenol (second monomer to first monomer)in the reaction system was calculated, and it was 0.51. Furthermore,from the melt viscosity of the recycled resin observed with thevibration type viscometer and the correlation equation of FIG. 14, theweight average molecular weight (Mw) of the recycled resin was estimatedto be 2.6×10³.

[S505: Determination of Whether the Molecular Weight of the RecycledResin Reaches the Set Value]

The weight average molecular weight (Mw) of the recycled resin at a flowrate of 14.7 kg/hr of the aqueous solution of formalin was 2.6×10³,which was smaller than the target range of 2.7×10³ to 3.3×10³, so thatit was determined that the molecular weight did not reach the set value.

[S506: Redetermination of the Amount of the Second Monomer (1st Time)]

In order to increase the molecular weight of the recycled resin, themolar ratio of formaldehyde to phenol (second monomer to first monomer)was redetermined to be 0.53, so that the flow rate of the aqueoussolution of formalin was increased from 14.7 kg/hr to 16.1 kg/hr usingthe formalin pump of the supply unit of the recycled resin manufacturingapparatus (pilot plant).

Incidentally, an operation to change the flow rate of the aqueoussolution of formalin was carried out while an operation of the recycledresin manufacturing apparatus (pilot plant) was not halted. Furthermore,other conditions except for the flow rate of the aqueous solution offormalin were not changed at all.

The melt viscosity of the recycled resin recovered through the steps offrom S502 to S505 was 406 mPa·s. From the relational expression of FIG.14, the weight average molecular weight (Mw) of the recycled resin wasestimated to be 3.6×10³, which was greater than the target range of2.7×10³ to 33×10³, so that it was determined that the molecular weightdid not reach the set value.

[S506: Redetermination of the Amount of the Second Monomer (2nd Time)]

In order to lower the molecular weight of the recycled resin, the molarratio of formaldehyde to phenol (second monomer to first monomer) wasredetermined to be 0.52, so that the flow rate of the aqueous solutionof formalin was lowered from 16.1 kg/hr to 15.6 kg/hr using the formalinpump of the supply unit of the recycled resin manufacturing apparatus(pilot plant).

Incidentally, an operation to change the flow rate of the aqueoussolution of formalin was carried out while an operation of the recycledresin manufacturing apparatus (pilot plant) was not halted. Furthermore,other conditions except for the flow rate of the aqueous solution offormalin were not changed at all.

Through the steps of from S502 to S505, the melt viscosity of therecovered recycled resin was 333 mPa·s. From the relational expressionof FIG. 14, the weight average molecular weight (Mw) of the recycledresin was estimated to be 3.0×10³, which was within the target range of2.7×10³ to 3.3×10³, so that it was determined that the molecular weightreached the set value.

[S507: Obtaining the Recycled Resin]

The flow rate of the aqueous solution of formalin was set to beconstant, i.e., 15.6 kg/hr, and the recycled resin manufacturingapparatus (pilot plant) was operated for about 6 hours to obtain arecycled resin.

After completion of operation of the recycled resin manufacturingapparatus (pilot plant), the obtained recycled resin was analyzed by GPCand as a result, the weight average molecular weight (Mw) was 3.2×10³,which was finally confirmed to be within the target range of 2.7×10³ to3.3×10³.

In the Example, the melt viscosity of the recycled resin is controlledby changing its set value of the flow rate of the formalin pumpmanually, whereby a recycled resin having a target molecular weight isobtained. However, these systems can also be controlled automatically.For example, the target value of the melt viscosity is set andinformation on the measured melt viscosity is fed back to the formalinpump such that the flow rate of the aqueous solution of formalin isPID-controlled, whereby a system can be implemented so as to obtain arecycled resin having a target melt viscosity.

The invention claimed is:
 1. A method for decomposing a polymermaterial, comprising: providing a polymer material containing a resincomponent composed of a first monomer which is a phenolic compound, anda second monomer which is an aldehyde compound; providing a plurality ofsample mixtures, each of which includes said polymer material and saidfirst monomer or a derivative of said first monomer, and has a differentsecond/first monomer ratio from each other, the second/first monomerratio being a molar ratio of an amount of the second monomer to anamount of the first monomer and the derivative of said first monomer ina reaction system for decomposing said resin component; decomposingchemically said resin component in the plurality of sample mixtures toobtain a plurality of sample chemical raw materials; measuring anaverage molecular weight of each of the plurality of sample chemical rawmaterials; acquiring data of a correlation between an average molecularweight of each of the plurality of sample chemical raw materials and asecond/first monomer ratio in each of the plurality of sample mixtureswhich generates the each of the plurality of sample chemical rawmaterials; determining a first range of the second/first monomer ratioin which when the second/first monomer ratio becomes small, themolecular weight of the chemical raw material becomes small; determininga second range of the second/first monomer ratio which is smaller thanand adjacent to the first range of the second/first monomer ratio, inwhich when the second/first monomer ratio becomes small, the molecularweight of the chemical raw material substantially does not change;determining a threshold value as a boundary value between the firstrange of the second/first monomer ratio and the second range of thesecond/first monomer ratio; determining a target average molecularweight of said chemical raw material; determining an addition amount ofsaid first monomer or the derivative of said first monomer to be addedto said polymer material based on said data of the correlation so thatsaid chemical raw material having the target average molecular weight isobtained by decomposing said resin component and so that thesecond/first monomer ratio is not less than the threshold value and lessthan 1.0; mixing said first monomer and the derivative of said firstmonomer in said addition amount with said polymer material to provide amixture of said polymer material and said first monomer and thederivative of said first monomer; and decomposing chemically said resincomponent in the mixture to produce said chemical raw material.
 2. Themethod for decomposing a polymer material according to claim 1, in whichthe method further comprises making said first monomer or the derivativeof said first monomer in said addition amount determined into asupercritical state or subcritical state, and said first monomer or thederivative of said first monomer in the mixture is made into asupercritical state or subcritical state.
 3. The method for decomposinga polymer material according to claim 1, in which said phenolic compoundis one or more kinds selected from phenol, o-cresol, m-cresol andp-cresol.
 4. The method for decomposing a polymer material according toclaim 1, in which said aldehyde compound is one or more kinds selectedfrom formaldehyde, paraformaldehyde, trioxane andhexamethylenetetramine.
 5. The method for decomposing a polymer materialaccording to claim 1, in which said polymer material contains acrosslinked polymer.
 6. The method for decomposing a polymer materialaccording to claim 5, in which said crosslinked polymer is a phenolresin.
 7. A method for decomposing a polymer material, comprising:providing a polymer material containing a resin component composed of afirst monomer which is a phenolic compound, and a second monomer whichis an aldehyde compound; providing a plurality of sample mixtures, eachof which includes said polymer material and said first monomer or aderivative of said first monomer, and has a different second/firstmonomer ratio from each other, the second/first monomer ratio being amolar ratio of an amount of the second monomer to an amount of the firstmonomer and the derivative of said first monomer in a reaction systemfor decomposing said resin component; decomposing chemically said resincomponent in the plurality of sample mixtures to obtain a plurality ofsample chemical raw materials; measuring an average molecular weight ofeach of the plurality of sample chemical raw materials; acquiring dataof a correlation between an average molecular weight of each of theplurality of sample chemical raw materials and a second/first monomerratio in each of the plurality of sample mixtures which generates theeach of the plurality of sample chemical raw materials; determining afirst range of the second/first monomer ratio in which when thesecond/first monomer ratio becomes small, the molecular weight of thechemical raw material becomes small; determining a second range of thesecond/first monomer ratio which is smaller than and adjacent to thefirst range of the second/first monomer ratio, in which when thesecond/first monomer ratio becomes small, the molecular weight of thechemical raw material substantially does not change; determining athreshold value as a boundary value between the first range of thesecond/first monomer ratio and the second range of the second/firstmonomer ratio; determining an addition amount of said first monomer orthe derivative of said first monomer to be added to said polymermaterial so that the second/first monomer ratio is approximately thethreshold value; mixing said first monomer and the derivative of saidfirst monomer in said addition amount with said polymer material toprovide a mixture of said polymer material and said first monomer andthe derivative of said first monomer; and decomposing chemically saidresin component in the mixture to produce said chemical raw material.